Conjugate of protein translation inhibitor and use thereof

Abstract

Provided are a conjugate of a protein translation inhibitor and use thereof in preparing a drug for treating and / or preventing a disease, wherein the disease is a tumor or cancer.

Description

The present application is based on and claims priority to Chinese Patent Application No. 2202410063661.2 filed on January 16, 2024, Chinese Patent Application No. 202411574559.5 filed on November 6, 2024, and Chinese Patent Application No. 202510025596.9 filed on January 7, 2025, which are incorporated herein by reference in their entirety. TECHNICAL FIELD The present disclosure pertains to the field of pharmaceutical chemistry, and particularly relates to a conjugate of a protein translation inhibitor and use thereof in the manufacture of a medicament for treating and / or preventing diseases. BACKGROUND Abnormal messenger RNA (mRNA) translation is a common hallmark of malignancies and manifests itself as the up-regulation of oncoproteins, growth factors, and signal transduction proteins associated with proliferation, survival, and metastasis. The expression of oncogenic drivers is tightly controlled by translation, and is regulated by the eukaryotic translation initiation factor 4F (eIF4F) complex. eIF4F mediates the recruitment of ribosomes to mRNA and initiates the translation of mRNA to protein. The eIF4F complex consists of three subunits: the mRNA 5' cap-binding protein eIF4E, the scaffold protein eIF4G, and the RNA helicase eIF4A. Hyperactivation of eIF4A is associated with a poor prognosis of related diseases, including lymphoma, lung cancer, colorectal cancer, liver cancer, breast cancer, and ovarian cancer. There are 3 eIF4A family members: eIF4A1, eIF4A2, and eIF4A3, all of which belong to a helicase protein family called DEAD-box. The family proteins all have 9 conserved motifs that are involved in RNA binding or ATP hydrolysis. There are reports that natural products can inhibit eIF4A-mediated translation and exhibit antiproliferative and anti-tumor phenotypes both in vivo and in vitro. For example, silvestrol and rocaglamide A have been shown to bind to and stabilize untranslated RNA / eIF4A complexes. These stable eIF4A^RocA complexes block scanning ribosomes, thereby inhibiting the translation of target mRNAs. Thus, the expression of related oncogenic factors is regulated through eIF4A-mediated translational inhibition. The present disclosure provides ligand-drug conjugates prepared from eIF4A inhibitors with a novel structure, which are expected to meet significant clinical needs in tumor treatment. SUMMARY Ligand-Drug Conjugate A first aspect of the present disclosure provides a ligand-drug conjugate or a racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or a mixture thereof, or a pharmaceutically acceptable salt or solvate thereof, wherein the ligand-drug conjugate consists of a ligand, a linking group, and a drug group, and the drug group is selected from a structure represented by formula I-A, II-A', III-A', IV-A, or V-A: wherein: M is selected from -N(Rm)-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-N(Rm)-, wherein the -(C1-C6)alkylene-O- and -(C1-C6)alkylene-N(Rm)- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; n is 0 or 1; W is absent or is selected from -(C1-C6)alkylene-, -O-, and -N(Rw)-, wherein the -(C1-C6)alkylene-is optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; U is selected from -(C1-C6)alkylene-, -(C3-C6)cycloalkylene-, and -(4-10 membered)heterocyclylene-, wherein the -(C1-C6)alkylene-, -(C3-C6)cycloalkylene-, and -(4-10 membered)heterocyclylene- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; Z is absent or is selected from -(C1-C6)alkylene-, -(C3-C6)cycloalkylene-, and -(4-10 membered)heterocyclylene-; Y is absent or is selected from -O-, -N(Ry)-, and -N+(Ry)2-, wherein Ry is selected from hydrogen, -(C1-C6)alkyl, -O(C1-C6)alkyl, -(C1-C6)haloalkyl, and -O-(C1-C6)haloalkyl, or Ry and Z form -(410 membered)heterocyclylene-, wherein the -(4-10 membered)heterocyclylene- is optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; R12 is selected from hydrogen, -(C1-C6)alkyl, -O-(C1-C6)alkyl, -(C=O)-(C1-C6)alkyl, -(C3-C6)cycloalkyl,   -O-(C3-C6)cycloalkyl,   -(4-10   membered)heterocyclyl,   and   -O-(4-10 membered)heterocyclyl, wherein the -(C1-C6)alkyl, -O-(C1-C6)alkyl, -(C=O)-(C1-C6)alkyl, -(C3-C6)cycloalkyl,   -O-(C3-C6)cycloalkyl,   -(4-10   membered)heterocyclyl,   and   -O-(4-10 membered)heterocyclyl are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; L is absent or is selected from -C(=O)-(C1-C6)alkylene-O-, -C(=O)-(C1-C6)alkylene-N(RL)-, -C(=O)-(C1-C6)alkylene-N+(RL)2-, -C(=O)NH-(C1-C6)alkylene-O-, -C(=O)NH-(C1-C6)alkylene-N(RL)-, and -C(=O)NH-(C1-C6)alkylene-N+(RL)2-, wherein RL is selected from hydrogen, -(C1-C6)alkyl, -O-(C1-C6)alkyl, -(C1-C6)haloalkyl, and -O-(C1-C6)haloalkyl, wherein the -C(=O)-(C1-C6)alkylene-O-, -C(=O)-(C1-C6)alkylene-N(RL)-, -C(=O)-(C1-C6)alkylene-N+(RL)2-, -C(=O)NH-(C1-C6)alkylene-O-, -C(=O)NH-(C1-C6)alkylene-N(RL)-, and -C(=O)NH-(C1-C6)alkylene-N+(RL)2- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; Q is selected from -N(Rq)-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-N(Rq)-, wherein the -(C1-C6)alkylene-O- and -(C1-C6)alkylene-N(Rq)- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; T is selected from -N(Rt)-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-N(Rt)-, wherein the -(C1-C6)alkylene-O- and -(C1-C6)alkylene-N(Rq)- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; Rm, Rw, Rq, and Rt are each independently selected from hydrogen, -(C1-C6)alkyl, -O-(C1-C6)alkyl, -(C1-C6)haloalkyl, and -O-(C1-C6)haloalkyl; X1 is selected from N and C(R1), wherein R1 is selected from hydrogen, halogen, cyano, -OH, -(C1-C6)alkyl, and -O-(C1-C6)alkyl; X2 is selected from N and C(R2), wherein R2 is selected from hydrogen, halogen, cyano, -OH, -(C1-C6)alkyl, and -O-(C1-C6)alkyl; R3 is selected from -(C3-C6)cycloalkyl, -(3-8 membered)heterocyclyl, -(C6-C10)aryl, and -(5-12 membered)heteroaryl, wherein the -(C3-C6)cycloalkyl, -(3-8 membered)heterocyclyl, -(C6- C10)aryl, and -(5-12 membered)heteroaryl are optionally substituted with one or more R31; ring A is selected from -(C3-C6)cycloalkylene-, -(3-8 membered)heterocyclylene-, -(C6-C10)arylene-, and -(5-12 membered)heteroarylene-, wherein the -(C3-C6)cycloalkylene-, -(3-8 membered)heterocyclylene-, -(C6-C10)arylene-, and -(5-12 membered)heteroarylene- are optionally substituted with one or more R31; each R31 is independently selected from oxo, hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C6)alkyl, -(C1-C6)alkylene-OH, -(C1-C6)alkylene-NH2, - (C1-C6)alkylene-NH[(C1-C6)alkyl], -(C1-C6)alkylene-N[(C1-C6)alkyl]2, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C 3-C6)cycloalkyl,     -(4-10 membered)heterocyclyl,     -O-(C3-C6)cycloalkyl,     -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2, -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2, -(C6-C10)aryl, -(5-12 membered)heteroaryl, -S(=O)2-NH2, -S(=O)2-NH(C1-C6)alkyl, -S(=O)2-N[(C1-C6)alkyl]2, -NH-C(=O)H, -NH-C(=O)-(C1-C6)alkyl, -N[(C1-C6)alkyl]-C(=O)-(C1-C6)alkyl, N[(C1-C6)alkyl]-C(=O)H, -NH-S(=O)2-(C1-C6)alkyl, -N[(C1-C6)alkyl]-S(=O)2-(C1-C6)alkyl, -P(=O)[(C1-C6)alkyl]2, -P(=O)[(C1-C6)alkyl]-NH2, -P(=O)[(C1-C6)alkyl]-NH(C1-C6)alkyl, and -P(=O)[(C1-C6)alkyl]-N[(C1-C6)alkyl]2, wherein the -(C1-C6)alkyl, -(C1-C6)alkylene-OH, -(C1-C6)alkylene-NH2, -(C1-C6)alkylene-NH[(C1-C6)alkyl], -(C1-C6)alkylene-N[(C1-C6)alkyl]2, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2, -(C6-C10)aryl, -(5-12 membered)heteroaryl, -S(=O)2-NH2, -S(=O)2-NH(C1-C6)alkyl, -S(=O)2-N[(C1-C6)alkyl]2, -NH-C(=O)H, -NH-C(=O)-(C1-C6)alkyl, -N[(C1-C6)alkyl]-C(=O)-(C1-C6)alkyl, N[(C1-C6)alkyl]-C(=O)H, -NH-S(=O)2-(C1-C6)alkyl, -N[(C1-C6)alkyl]-S(=O)2-(C1-C6)alkyl, -P(=O)[(C1-C6)alkyl]2, -P(=O)[(C1-C6)alkyl]-NH2, -P(=O)[(C1-C6)alkyl]-NH(C1-C6)alkyl, and -P(=O)[(C1-C6)alkyl]-N[(C1-C6)alkyl]2 are optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -(C1-C6)alkylene-OH, -NH2, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C1-C6)alkylene-NH2, -(C1-C6)alkylene-NH[(C1-C6)alkyl], -(C1-C6)alkylene-N[(C1-C6)alkyl]2, -(C6-C10)aryl, -(5-12 membered)heteroaryl, -(C1-C6)alkylene-O(C1-C6)alkyl, and oxo; R4 is selected from hydrogen, halogen, cyano, -OH, -NH2, -(C1-C6)alkyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -(C3-C6)cycloalkyl, -O-(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(4-10 membered)heterocyclyl, -(C6-C10)aryl, -O-(C6-C10)aryl, -(5-12 membered)heteroaryl, and -O-(5-12 membered)heteroaryl; X is selected from O, S, NH, N[(C1-C6)alkyl], N[C(=O)-Rc], C(Ra)(Rb), C(=O), C[=C(Ra)Rb], S(=O), and S(=O)2; Ra and Rb are each independently selected from hydrogen, halogen, cyano, -ORc, -SRc, -N(Rc)Rc, -(C1-C6)alkyl, and -(C1-C6)haloalkyl; Rc is selected from hydrogen, -(C1-C6)alkyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -(C3-C6)cycloalkyl, -O-(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(4-10 membered)heterocyclyl, -(C6-C10)aryl, -O-(C6-C10)aryl, -(5-12 membered)heteroaryl, and -O-(512 membered)heteroaryl; ring B is selected from -(C6-C10)aryl and -(5-12 membered)heteroaryl, or ring B is selected from -(C6-C10)arylene- and -(5-12 membered)heteroarylene-, wherein the -(C6-C10)arylene- and -(5-12 membered)heteroarylene- are optionally substituted with one or more groups selected from R5 and R6; R5 and R6 are each independently selected from hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2, -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2, -C(=O)-H, and -C(=N-OH)-H, wherein the -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH(C1-C6)alkyl, and -C(=O)-N[(C1-C6)alkyl]2 are optionally substituted with one or more groups selected from hydrogen, halogen, oxo, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and N[(C1-C4)alkyl]2; or R5 and R6, together with the carbon atoms to which they are attached, form 5-membered heterocyclyl; ring C is selected from -(C6-C10)aryl and -(5-12 membered)heteroaryl, or ring C is selected from -(C6-C10)arylene- and -(5-12 membered)heteroarylene-, wherein the -(C6-C10)arylene- and -(5-12 membered)heteroarylene- are optionally substituted with one or more R7; each R7 is independently selected from hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2, -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2, and -NHC(=O)-(C1-C6)alkyl, wherein the -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, - O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2, and -NHC(=O)-(C1-C6)alkyl are optionally substituted with one or more groups selected from hydrogen, halogen, oxo, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; m is 1, 2, 3, 4, or 5; R8a, R8b, R9a, and R9b are each independently selected from hydrogen, halogen, cyano, -(C1-C6)alkyl, -(C1-C6)haloalkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -OR, -N(R)R, -[(C1-C8)alkylene]R, -[(C1-C8)alkylene]OR, -[(C1-C8)alkylene]N(R)R, -[(C1-C8)alkylene]N(R)C(=O)R, -[(C1-C8)alkylene]N(R)C(=O)N(R)R, -C(=O)R, -C(=O)N(R)R, -C(=O)[(C1-C8)alkylene]N(R)R, -C(=O)OR, -C(=S)N(R)R, -SR, -S(=O)R, -S(=O)2R, -S(=O)2N(R)R, -N(R)C(=O)R, -N(R)C(=O)N(R)R, -P(=O)(OR)(OR), -(C6-C10)aryl, -(5-12 membered)heteroaryl, -(C3-C6)cycloalkyl, and -(4-10 membered)heterocyclyl, wherein each R is independently selected from hydrogen, -OH, -NH2, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -(C1-C4)alkylene-O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -S(=O)2-(C1-C6)alkyl, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-H, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2,   -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2,   -[(C1- C6)alkylene]-(C3-C6)cycloalkyl,-[(C1-C6)alkylene]-(4-10 membered)heterocyclyl, -(C6-C10)aryl,-[(C1-C6)alkylene]-(C6-C10)aryl, and -(5-12 membered)heteroaryl, wherein the -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -(C1-C4)alkylene-O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -S(=O)2-(C1-C6)alkyl, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2, -[(C1-C6)alkylene]-(C3-C6)cycloalkyl, -[(C1-C6)alkylene]-(4-10 membered)heterocyclyl, -(C6-C10)aryl, -[(C1-C6)alkylene]-(C6-C10)aryl, and -(5-12 membered)heteroaryl are optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, N[(C1-C4)alkyl]2, and (C1-C4)alkyl; or R8a and R8b are combined to form oxo, -(C2-C6)alkenyl, -(C3-C6)cycloalkyl, or -(4-10 membered)heterocyclyl; or R9a and R9b are combined to form oxo, -(C2-C6)alkenyl, -(C3-C6)cycloalkyl, or -(4-10 membered)heterocyclyl; or R8a and R9a, together with the carbon atoms to which they are attached, form (C3-C6)cycloalkyl, (4-10 membered)heterocyclyl, or (5-10 membered)heteroaryl, wherein the aforementioned group is optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl,    -N[(C1-C4)alkyl]2,    -(C3-C6)cycloalkyl,    -(4-8 membered)heterocyclyl, -(5-6 membered)heteroaryl, and -(C6-C10)aryl; or R8b and R9b, together with the carbon atoms to which they are attached, form (C3-C6)cycloalkyl, (4-10 membered)heterocyclyl, or (5-10 membered)heteroaryl, wherein the aforementioned group is optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl,    -N[(C1-C4)alkyl]2,    -(C3-C6)cycloalkyl,    -(4-8 membered)heterocyclyl, -(5-6 membered)heteroaryl, and -(C6-C10)aryl; R10 is selected from hydrogen, cyano, -OH, and -NH2, or R10 and R9a, together with the atoms to which they are attached, form (5-6 membered)heterocyclyl, wherein the (5-6 membered)heterocyclyl is optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -(C1-C4)alkyl, -(C3-C6)cycloalkyl, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2. The first aspect of the present disclosure further provides a ligand-drug conjugate or a racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or a mixture thereof, or a pharmaceutically acceptable salt or solvate thereof, wherein the ligand-drug conjugate consists of a ligand, a linking group, and a drug group, and the drug group is selected from a structure represented by formula I-A, II-A, III-A, IV-A, or V-A: wherein: M is selected from -N(Rm)-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-N(Rm)-, wherein the -(C1-C6)alkylene-O- and -(C1-C6)alkylene-N(Rm)- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1- C4)alkyl, and -N[(C1-C4)alkyl]2; W is absent or is selected from -(C1-C6)alkylene-, -O-, and -N(Rw)-, wherein the -(C1-C6)alkylene-is optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; U is selected from -(C1-C6)alkylene-, -(C3-C6)cycloalkylene-, and -(4-10 membered)heterocyclylene-, wherein the -(C1-C6)alkylene-, -(C3-C6)cycloalkylene-, and -(4-10 membered)heterocyclylene- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; Z is absent or is selected from -(C1-C6)alkylene-, -(C3-C6)cycloalkylene-, and -(4-10 membered)heterocyclylene-; Y is absent or is selected from -O- and -N(Ry)-, wherein Ry is selected from hydrogen, -(C1-C6)alkyl, -O(C1-C6)alkyl, -(C1-C6)haloalkyl, and -O-(C1-C6)haloalkyl, or Ry and Z form -(4-10 membered)heterocyclylene-, wherein the -(4-10 membered)heterocyclylene- is optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; R12 is selected from hydrogen, -(C1-C6)alkyl, -O-(C1-C6)alkyl, -(C=O)-(C1-C6)alkyl, -(C3-C6)cycloalkyl,   -O-(C3-C6)cycloalkyl,   -(4-10   membered)heterocyclyl,   and   -O-(4-10 membered)heterocyclyl, wherein the -(C1-C6)alkyl, -O-(C1-C6)alkyl, -(C=O)-(C1-C6)alkyl, -(C3-C6)cycloalkyl,   -O-(C3-C6)cycloalkyl,   -(4-10   membered)heterocyclyl,   and   -O-(4-10 membered)heterocyclyl are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; Q is selected from -N(Rq)-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-N(Rq)-, wherein the -(C1-C6)alkylene-O- and -(C1-C6)alkylene-N(Rq)- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; T is selected from -N(Rt)-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-N(Rt)-, wherein the -(C1-C6)alkylene-O- and -(C1-C6)alkylene-N(Rq)- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; Rm, Rw, Rq, and Rt are each independently selected from hydrogen, -(C1-C6)alkyl, -O-(C1-C6)alkyl, -(C1-C6)haloalkyl, and -O-(C1-C6)haloalkyl; X1 is selected from N and C(R1), wherein R1 is selected from hydrogen, halogen, cyano, -OH, -(C1-C6)alkyl, and -O-(C1-C6)alkyl; X2 is selected from N and C(R2), wherein R2 is selected from hydrogen, halogen, cyano, -OH, - (C1-C6)alkyl, and -O-(C1-C6)alkyl; R3 is selected from -(C3-C6)cycloalkyl, -(3-8 membered)heterocyclyl, -(C6-C10)aryl, and -(5-12 membered)heteroaryl, and R3 is optionally substituted with one or more R31; ring A is selected from -(C3-C6)cycloalkylene-, -(3-8 membered)heterocyclylene-, -(C6-C10)arylene-, and -(5-12 membered)heteroarylene-, and ring A is optionally substituted with one or more R31; each R31 is independently selected from oxo, hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C6)alkyl, -(C1-C6)alkylene-OH, -(C1-C6)alkylene-NH2, -(C1-C6)alkylene-NH[(C1-C6)alkyl], -(C1-C6)alkylene-N[(C1-C6)alkyl]2, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl,     -(4-10 membered)heterocyclyl,     -O-(C3-C6)cycloalkyl,     -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2, -C(=O)-NH(C1-C6)alkyl, and -C(=O)-N[(C1-C6)alkyl]2, wherein the -(C1-C6)alkyl, -(C1-C6)alkylene-OH, -(C1-C6)alkylene-NH2, -(C1-C6)alkylene-NH[(C1-C6)alkyl], -(C1-C6)alkylene-N[(C1-C6)alkyl]2, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH(C1-C6)alkyl, and -C(=O)-N[(C1-C6)alkyl]2 are optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -(C1-C6)alkylene-OH, -NH2, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C1-C6)alkylene-NH2, -(C1-C6)alkylene-NH[(C1-C6)alkyl], and -(C1-C6)alkylene-N[(C1-C6)alkyl]2; R4 is selected from hydrogen, halogen, cyano, -OH, -NH2, -(C1-C6)alkyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -(C3-C6)cycloalkyl, -O-(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(4-10 membered)heterocyclyl, -(C6-C10)aryl, -O-(C6-C10)aryl, -(5-12 membered)heteroaryl, and -O-(5-12 membered)heteroaryl; X is selected from O, S, NH, N[(C1-C6)alkyl], N[C(=O)-Rc], C(Ra)(Rb), C(=O), C[=C(Ra)Rb], S(=O), and S(=O)2; Ra and Rb are each independently selected from hydrogen, halogen, cyano, -ORc, -SRc, -N(Rc)Rc, -(C1-C6)alkyl, and -(C1-C6)haloalkyl; Rc is selected from hydrogen, -(C1-C6)alkyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -(C3-C6)cycloalkyl, -O-(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(4-10 membered)heterocyclyl, -(C6-C10)aryl, -O-(C6-C10)aryl, -(5-12 membered)heteroaryl, and -O-(512 membered)heteroaryl; ring B is selected from -(C6-C10)aryl and -(5-12 membered)heteroaryl, or ring B is selected from - (C6-C10)arylene- and -(5-12 membered)heteroarylene-, wherein the -(C6-C10)arylene- and -(5-12 membered)heteroarylene- are optionally substituted with one or more groups selected from R5 and R6; R5 and R6 are each independently selected from hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2, -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2, -C(=O)-H, and -C(=N-OH)-H, wherein the -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH(C1-C6)alkyl, and -C(=O)-N[(C1-C6)alkyl]2 are optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and N[(C1-C4)alkyl]2; or R5 and R6, together with the carbon atoms to which they are attached, form 5-membered heterocyclyl; ring C is selected from -(C6-C10)aryl and -(5-12 membered)heteroaryl, or ring C is selected from -(C6-C10)arylene- and -(5-12 membered)heteroarylene-, wherein the -(C6-C10)arylene- and -(5-12 membered)heteroarylene- are optionally substituted with one or more R7; each R7 is independently selected from hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2, -C(=O)-NH(C1-C6)alkyl, and -C(=O)-N[(C1-C6)alkyl]2, wherein the -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH(C1-C6)alkyl, and -C(=O)-N[(C1-C6)alkyl]2 are optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2; m is 1, 2, 3, 4, or 5; R8a, R8b, R9a, and R9b are each independently selected from hydrogen, halogen, cyano, -(C1-C6)alkyl, -(C1-C6)haloalkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -OR, -N(R)R, -[(C1-C8)alkylene]R, -[(C1-C8)alkylene]OR, -[(C1-C8)alkylene]N(R)R, -C(=O)R, -C(=O)N(R)R, -C(=O)[(C1-C8)alkylene]N(R)R, -C(=O)OR, -C(=S)N(R)R, -SR, -S(=O)R, -S(=O)2R, -S(=O)2N(R)R, -N(R)C(=O)R, -N(R)C(=O)N(R)R, -P(=O)(OR)(OR), -(C6-C10)aryl, -(5-12 membered)heteroaryl, -(C3-C6)cycloalkyl, and -(4-10 membered)heterocyclyl, wherein each R is independently selected from hydrogen, -OH, -NH2, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-H, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2, -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2, -[(C1-C6)alkylene]-(4-10 membered)heterocyclyl, -(C6-C10)aryl, -[(C1-C6)alkylene]-(C6-C10)aryl, and -(5-12 membered)heteroaryl, wherein the -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2, -[(C1-C6)alkylene]-(4-10 membered)heterocyclyl, -(C6-C10)aryl, -[(C1-C6)alkylene]-(C6-C10)aryl, and -(5-12 membered)heteroaryl are optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and N[(C1-C4)alkyl]2; or R8a and R8b, and R9a and R9b are independently combined to form oxo, -(C2-C6)alkenyl, -(C3-C6)cycloalkyl, or -(4-10 membered)heterocyclyl; or R8a and R9a, and R8b and R9b, together with the carbon atoms to which they are attached, form (C3-C6)cycloalkyl, (4-10 membered)heterocyclyl, or (5-10 membered)heteroaryl, wherein the aforementioned group is optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -(5-6 membered)heteroaryl, and -(C6-C10)aryl; R10 is selected from hydrogen, cyano, -OH, and -NH2, or R10 and R9a, together with the atoms to which they are attached, form (5-6 membered)heterocyclyl, wherein the (5-6 membered)heterocyclyl is optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -(C1-C4)alkyl, -(C3-C6)cycloalkyl, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2. In certain embodiments, the drug group is selected from a structure represented by formula I-A: I-A, wherein X, X1, X2, ring B, ring C, R3, R4, R5, R6, R8a, R8b, R9a, R9b, R10, and M are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, Rm is selected from hydrogen, -(C1-C4)alkyl, -O-(C1-C4)alkyl, -(C1-C4)haloalkyl, and -O-(C1-C4)haloalkyl. In certain embodiments,Rm is selected from hydrogen, methyl, ethyl, propyl, -O-methyl, -O-ethyl, and -O-propyl. In certain embodiments,Rm is hydrogen. In certain embodiments, M is selected from -NH-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-NH-, wherein the -(C1-C6)alkylene-O- and -(C1-C6)alkylene-NH- are optionally substituted with 1, 2, or 3 groups selected from hydrogen, halogen, -OH, -O-methyl, -NH2, -NH-methyl, -N(methyl)2, and -N(ethyl)2. In certain embodiments, M is selected from -NH-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-NH-. In certain embodiments, M is selected from -NH-, -O-, -(C1-C4)alkylene-O-, and -(C1-C4)alkylene-NH-. In certain embodiments, M is selected from -NH-, -O-, -CH2O-, and -CH2NH-. In certain embodiments, M is selected from -NH-, -O-, *-CH2O-, and *-CH2NH-, wherein the * end is attached to ring C. In certain embodiments, M is selected from -NH-. In certain embodiments, ring C is selected from -(C6-C10)arylene- and -(5-10 membered)heteroarylene-, wherein the -(C6-C10)arylene- and -(5-10 membered)heteroarylene- are optionally substituted with 1, 2, or 3 R7. In certain embodiments, ring C is selected from phenylene, naphthylene, and (5-6 membered)heteroarylene, wherein the phenylene, naphthylene, and (5-6 membered)heteroarylene are optionally substituted with 1 or 2 R7. In certain embodiments, ring C is phenylene, wherein the phenylene is optionally substituted with 1 R7. In certain embodiments, each R7 is independently selected from hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3- C6)cycloalkyl, -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, and -O-(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, and -O-(4-8 membered)heterocyclyl are optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2. In certain embodiments, each R7 is independently selected from hydrogen, halogen, cyano, -OH, -NH2, -(C1-C4)alkylene-OH, -(C1-C4)alkylene-NH(C1-C4)alkyl, -(C1-C4)alkylene-N[(C1-C4)alkyl]2, and -(C1-C4)alkylene-NH2. In certain embodiments, each R7 is independently selected from hydrogen, fluorine, chlorine, bromine, -OH, -NH2, -CH2OH, and -CH2NH2. In certain embodiments, each R7 is independently selected from hydrogen. / \ * UL J In certain embodiments, ring C is             , wherein the * end is attached to M. In certain embodiments, the drug group is selected from a structure represented by formula II-A': II-A', wherein X, X1, X2, ring B, ring C, R3, R4, R5, R6, R7, m, W, U, Z, and Y are defined as described in any one of the embodiments of the present disclosure, and n is 0 or 1. In certain embodiments, the drug group is selected from a structure represented by formula II-A: II-A, wherein X, X1, X2, ring B, ring C, R3, R4, R5, R6, R7, m, W, U, Z, and Y are defined as described in any one of the embodiments of the present disclosure. In certain embodiments,Rw and Ryare each independently selected from hydrogen, -(C1-C4)alkyl, -O-(C1-C4)alkyl, -(C1-C4)haloalkyl, and -O-(C1-C4)haloalkyl. In certain embodiments,Rw and Ryare each independently selected from hydrogen, methyl, ethyl, propyl, -O-methyl, -O-ethyl, and -O-propyl. In certain embodiments,Rw is selected from hydrogen and methyl. In certain embodiments,Ry is hydrogen. In certain embodiments, W is absent or is selected from -(C1-C6)alkylene-, -NH-, -N[(C1-C6)alkyl]-, and -N[O(C1-C6)alkyl]-. In certain embodiments, W is absent or is selected from -(C1-C4)alkylene, -NH-, and -N[-(C1-C4)alkyl]-. In certain embodiments, W is absent or is selected from methylene, ethylene, -NH-, -N(Me)-, and -N(Et)-. In certain embodiments, W is absent or is selected from -NH- and -N(Me)-. In certain embodiments, U is selected from -(C1-C6)alkylene-, -(C3-C6)cycloalkylene-, and -(4-10 membered)heterocyclylene-. In certain embodiments, U is selected from -(C1-C4)alkylene-, -(C3-C6)cycloalkylene-, and -(4-6 membered)heterocyclylene-. In certain embodiments, U is selected from methylene, ethylene, cyclopropylene, azetidinylene, and pyrrolidinylene. I—nO—i In certain embodiments, U is selected from methylene, ethylene, and *         \ * I—j     * I—\ / N—j In certain embodiments, U is selected from methylene, ethylene, v , and ’ v , wherein the * end is attached to W, and when W is absent, the * end is attached to carbonyl. In certain embodiments, Z is absent or is selected from -(C1-C4)alkylene-, -(C3-C6)cycloalkylene-, and -(4-6 membered)heterocyclylene-. In certain embodiments, Z is absent or is selected from methylene, ethylene, cyclopropylene, azetidinylene, and pyrrolidinylene. In certain embodiments, Z is absent. In certain embodiments, Y is absent or is selected from -O-, -N(Ry)-, and -N+(Ry)2-, wherein Ry is selected from hydrogen, -(C1-C6)alkyl, and -O(C1-C6)alkyl, or Ry and Z form -(4-10 membered)heterocyclylene-. In certain embodiments, Y is absent or is selected from -O-, -N(Ry)-, and -N+(Ry)2-, wherein Ry is selected from hydrogen, -(C1-C4)alkyl, and -O(C1-C4)alkyl, or Ry and Z form -(4-6 membered)heterocyclylene-. In certain embodiments, Y is absent or is selected from -O-, -N(Ry)-, and -N+(Ry)2-, wherein Ry is selected from hydrogen, methyl, ethyl, and -O-methyl. In certain embodiments, Y is selected from -O-, -NH-, -N(CH3)-, and -N+(CH3)2-. In certain embodiments, Y is absent or is selected from -O- and -N(Ry)-, wherein Ry is selected from hydrogen, -(C1-C6)alkyl, and -O(C1-C6)alkyl, or Ry and Z form -(4-10 membered)heterocyclylene-. In certain embodiments, Y is absent or is selected from -O- and -N(Ry)-, wherein Ry is selected from hydrogen, -(C1-C4)alkyl, and -O(C1-C4)alkyl, or Ry and Z form -(4-6 membered)heterocyclylene-. In certain embodiments, Y is absent or is selected from -O- and -N(Ry)-, wherein Ry is selected from hydrogen, methyl, ethyl, and -O-methyl. In certain embodiments, Y is selected from -O- and -NH-. In certain embodiments, the structural unit -W-U-Z-Y- is selected from -N(Rw)-(C1-C6)alkylene-N(Ry)-, -N(Rw)-(C1-C6)alkylene-N+(Ry)2-, -N(Rw)-(C1-C6)alkylene-O-, -(C1-C6)alkylene-N(Ry)-, -(C1-C6)alkylene-O-,     -(C3-C6)cycloalkylene-N(Ry)-,     -(C1-C6)alkylene-N+(Ry)2-,     -(C3- C6)cycloalkylene-O-, -(4-6 membered)heterocyclylene-O-, -(4-6 membered)heterocyclylene-N(Ry)-, and -N(Rw)-(4-6 membered)heterocyclylene-, wherein the -N(Rw)-(C1-C6)alkylene-N(Ry)-, -N(Rw)-(C1-C6)alkylene-N+(Ry)2-, -N(Rw)-(C1-C6)alkylene-O-, -(C1-C6)alkylene-N(Ry)-, -(C1-C6)alkylene-N+(Ry)2-,      -(C1-C6)alkylene-O-,      -(C3-C6)cycloalkylene-N(Ry)-,      -(C3- C6)cycloalkylene-O-, -(4-6 membered)heterocyclylene-O-, -(4-6 membered)heterocyclylene-N(Ry)-, and -N(Rw)-(4-6 membered)heterocyclylene- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2. In certain embodiments, the structural unit -W-U-Z-Y- is selected from -N(Rw)-(C1-C6)alkylene-N(Ry)-, -N(Rw)-(C1-C6)alkylene-N+(Ry)2-, -N(Rw)-(C1-C6)alkylene-O-, -(C1-C6)alkylene-N(Ry)-, -(C1-C6)alkylene-N+(Ry)2-, -(C1-C6)alkylene-O-, -(4-6 membered)heterocyclylene-O-, -(4-6 membered)heterocyclylene-N(Ry)-, and -N(Rw)-(4-6 membered)heterocyclylene-. In certain embodiments, the structural unit -W-U-Z-Y- is selected from *-NH-CH2-CH2-NH-, *-N(CH3)-CH2-CH2-NH-, *-NH-CH2-CH2-O-, *-CH2-O-, *-CH2-NH-, *-CH2-N(CH3)-, *-CH2- ' N^\   , A. N+(CH3)2-,       0\ and H , wherein the * end is attached to carbonyl. In certain embodiments, the structural unit -W-U-Z-Y- is selected from -N(Rw)-(C1-C6)alkylene-N(Ry)-, -N(Rw)-(C1-C6)alkylene-O-, -(C1-C6)alkylene-N(Ry)-, -(C1-C6)alkylene-O-, -(C3-C6)cycloalkylene-N(Ry)-, -(C3-C6)cycloalkylene-O-, -(4-6 membered)heterocyclylene-O-, -(4-6 membered)heterocyclylene-N(Ry)-, and -N(Rw)-(4-6 membered)heterocyclylene-, wherein the -N(Rw)-(C1-C6)alkylene-N(Ry)-, -N(Rw)-(C1-C6)alkylene-O-, -(C1-C6)alkylene-N(Ry)-, -(C1-C6)alkylene-O-,      -(C3-C6)cycloalkylene-N(Ry)-,      -(C3-C6)cycloalkylene-O-,      -(4-6 membered)heterocyclylene-O-, -(4-6 membered)heterocyclylene-N(Ry)-, and -N(Rw)-(4-6 membered)heterocyclylene- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2. In certain embodiments, the structural unit -W-U-Z-Y- is selected from -N(Rw)-(C1-C6)alkylene-N(Ry)-, -N(Rw)-(C1-C6)alkylene-O-, -(C1-C6)alkylene-N(Ry)-, -(C1-C6)alkylene-O-, -(4-6 membered)heterocyclylene-O-, -(4-6 membered)heterocyclylene-N(Ry)-, and -N(Rw)-(4-6 membered)heterocyclylene-. In certain embodiments, the structural unit -W-U-Z-Y- is selected from *-NH-CH2-CH2-NH-, *-* X N(CH3)-CH2-CH2-NH-, *-NH-CH2-CH2-O-, *-CH2-O-, *-CH2-NH-,         o , and * /  J—J r N                               .                       .                                                                                                    . H         , wherein the * end is attached to carbonyl.For example, the structural unit -W-U- * X. Z-Y- is selected from *-NH-CH2-CH2-NH- and        C)A, wherein the * end is attached to carbonyl. In certain embodiments, the drug group is selected from a structure represented by formula III-A': III-A', wherein X, X1, X2, ring B, ring C, L, R3, R4, R5, R6, R7, m, R8a, R8b, and R12 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the drug group is selected from a structure represented by formula III-A: III-A, wherein X, X1, X2, ring B, ring C, R3, R4, R5, R6, R7, m, R8a, R8b, and R12 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R12 is selected from hydrogen, -(C1-C6)alkyl, -O-(C1-C6)alkyl, -(C=O)- (C1-C6)alkyl, -(C3-C6)cycloalkyl, -O-(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, and -O-(4-10 membered)heterocyclyl. In certain embodiments, R12 is selected from hydrogen, -(C1-C4)alkyl, -O-(C1-C4)alkyl, -(C=O)-(C1-C4)alkyl, -(C3-C6)cycloalkyl, and -O-(C3-C6)cycloalkyl. In certain embodiments, R12 is selected from hydrogen, -(C1-C4)alkyl, -O-(C1-C4)alkyl, and -(C3-C6)cycloalkyl. In certain embodiments, R12 is selected from hydrogen and -(C1-C4)alkyl. In certain embodiments, R12 is selected from hydrogen, methyl, and ethyl. In certain embodiments, R12 is selected from hydrogen and methyl. In certain embodiments, R12 is selected from hydrogen. In certain embodiments, L is absent or is selected from -C(=O)-(C1-C4)alkylene-O-, -C(=O)-(C1-C4)alkylene-N(RL)-, -C(=O)-(C1-C4)alkylene-N+(RL)2-, -C(=O)NH-(C1-C4)alkylene-O-, -C(=O)NH-(C1-C4)alkylene-N(RL)-, and -C(=O)NH-(C1-C4)alkylene-N+(RL)2-, wherein RL is selected from hydrogen, -(C1-C4)alkyl, and -(C1-C4)haloalkyl. In certain embodiments, L is absent or is selected from -C(=O)-(C1-C4)alkylene-O-, -C(=O)-(C1-C4)alkylene-N(RL)-, and -C(=O)-(C1-C4)alkylene-N+(RL)2-, wherein RL is selected from hydrogen, methyl, and ethyl. In certain embodiments, L is absent or is selected from -C(=O)CH2O-, -C(=O)CH2CH2O-, -C(=O)CH2N(RL)-, -C(=O)CH2CH2N(RL)-, -C(=O)CH2N+(RL)2-, and -C(=O)CH2CH2N+(RL)2-, wherein RL is selected from hydrogen, methyl, and ethyl. In certain embodiments, L is absent or is selected from *-C(=O)CH2O-, *-C(=O)CH2N(CH3)-, and *-C(=O)CH2N+(CH3)2-, wherein the * end is attached to N. In certain embodiments, L is absent. In certain embodiments, the drug group is selected from a structure represented by formula IV-A: IV-A, wherein X, X1, X2, ring B, ring C, R3, R4, Q, R7, m, R8a, R8b, R9a, R9b, and R10 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments,Rq is selected from hydrogen, -(C1-C4)alkyl, -O-(C1-C4)alkyl, -(C1-C4)haloalkyl, and -O-(C1-C4)haloalkyl. In certain embodiments,Rq is selected from hydrogen, methyl, ethyl, propyl, -O-methyl, -O-ethyl, and -O-propyl. In certain embodiments,Rq is hydrogen. In certain embodiments, Q is selected from -NH-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-NH-, wherein the -(C1-C6)alkylene-O- and -(C1-C6)alkylene-NH- are optionally substituted with 1, 2, or 3 groups selected from hydrogen, halogen, -OH, -O-methyl, -NH2, -NH-methyl, -N(methyl)2, and -N(ethyl)2. In certain embodiments, Q is selected from -NH-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-NH-. In certain embodiments,Q is selected from -NH-, -O-, -(C1-C4)alkylene-O-, and -(C1-C4)alkylene-NH-. In certain embodiments,Q is selected from -NH-, -O-, -CH2O-, and -CH2NH-. In certain embodiments,Q is selected from -NH-, -O-, *-CH2O-, and *-CH2NH-, wherein the * end is attached to ring B. In certain embodiments, Q is selected from -NH-. In certain embodiments, ring B is selected from -(C6-C10)arylene- and (5-10 membered)heteroarylene-, wherein the -(C6-C10)arylene- and (5-10 membered)heteroarylene- are optionally substituted with 1, 2, or 3 groups selected from R5 and R6. In certain embodiments, ring B is selected from phenylene, naphthylene, and (5-6 membered)heteroarylene, wherein the phenylene, naphthylene, and (5-6 membered)heteroarylene are optionally substituted with 1 or 2 groups selected from R5 and R6. In certain embodiments, ring B is phenylene, wherein the phenylene is optionally substituted with 1 R5 or R6. In certain embodiments, R5 and R6 are each independently selected from hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, and -O-(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, and -O-(4-8 membered)heterocyclyl are optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and N[(C1-C4)alkyl]2. In certain embodiments, R5 and R6 are each independently selected from hydrogen, halogen, cyano, -OH, -NH2, -(C1-C4)alkyl, -(C1-C4)alkyl-OH, -(C1-C4)alkyl-NH2, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, and -(C3-C6)cycloalkyl. In certain embodiments, R5 is selected from hydrogen, fluorine, chlorine, bromine, cyano, -OH, -NH2, and -CH2NH2. In certain embodiments, R5 is selected from hydrogen, -OH, -NH2, and -CH2NH2. In certain embodiments, R5 is selected from hydrogen. In certain embodiments, R6 is selected from hydrogen, fluorine, chlorine, bromine, cyano, -OH, -NH2, -O-methyl, and cyclopropyl. In certain embodiments, R6 is selected from hydrogen, fluorine, chlorine, bromine, cyano, -OH, -NH2, and -O-methyl. In certain embodiments, R6 is selected from hydrogen, cyano, and -O-methyl. In certain embodiments, R6 is selected from cyano and -O-methyl. In certain embodiments, R6 is cyano. In certain embodiments, R6 is hydrogen. In certain embodiments, ring B is , wherein the * end is attached to Q. In certain embodiments, the drug group is selected from a structure represented by formula V-A: V-A, wherein X, X1, X2, T, ring A, ring B, ring C, R4, R5, R6, R7, m, R8a, R8b, R9a, R9b, and R10 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments,Rt is selected from hydrogen, -(C1-C4)alkyl, -O-(C1-C4)alkyl, -(C1-C4)haloalkyl, and -O-(C1-C4)haloalkyl. In certain embodiments,Rt is selected from hydrogen, methyl, ethyl, propyl, -O-methyl, -O-ethyl, and -O-propyl. In certain embodiments,Rt is hydrogen. In certain embodiments, T is selected from -NH-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-NH-, wherein the -(C1-C6)alkylene-O- and -(C1-C6)alkylene-NH- are optionally substituted with 1, 2, or 3 groups selected from hydrogen, halogen, -OH, -O-methyl, -NH2, -NH-methyl, -N(methyl)2, and -N(ethyl)2. In certain embodiments, T is selected from -NH-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-NH-. In certain embodiments, T is selected from -NH-, -O-, -(C1-C4)alkylene-O-, and -(C1-C4)alkylene- NH-. In certain embodiments, T is selected from -NH-, -O-, -CH2O-, and -CH2NH-. In certain embodiments, T is selected from -NH-, -O-, *-CH2O-, and *-CH2NH-, wherein the * end is attached to ring A. In certain embodiments, T is selected from -NH-, *-CH2O-, and *-CH2NH-, wherein the * end is attached to ring A. In certain embodiments, T is selected from -NH- and *-CH2NH-, wherein the * end is attached to ring A. In certain embodiments, T is selected from -NH-. In certain embodiments,ring A is selected from -(C3-C6)cycloalkylene-, -(4-6 membered)heterocyclylene-, -(C6-C10)arylene-, and -(5-12 membered)heteroarylene-, wherein the -(C3-C6)cycloalkylene-, -(4-6 membered)heterocyclylene-, -(C6-C10)arylene-, and -(5-12 membered)heteroarylene are optionally substituted with one or more R31. In certain embodiments, theR31 is selected from oxo, hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C4)alkyl, -(C1-C4)alkylene-OH, -(C1-C4)alkylene-NH2, -(C1-C4)alkylene-NH(C1-C4)alkyl, -(C1-C4)alkylene-N[(C1-C4)alkyl]2, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl,      -(4-8 membered)heterocyclyl,      -O-(C3-C6)cycloalkyl,      -O-(4-8 membered)heterocyclyl, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C4)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2, -C(=O)-NH(C1-C4)alkyl, and -C(=O)-N[(C1-C4)alkyl]2. In certain embodiments, R31 is selected from oxo, hydrogen, halogen, cyano, -OH, -SH, -NH2, -(C1-C4)alkyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -NH-(C1-C4)alkyl, -(C1-C4)alkylene-OH, -(C1-C4)alkylene-NH2, -(C1-C4)alkylene-NH(C1-C4)alkyl, and -(C1-C4)alkylene-N[(C1-C4)alkyl]2. In certain embodiments, R31 is selected from oxo, hydrogen, fluorine, chlorine, cyano, -OH, -SH, -NH2, methyl, halomethyl, -O-methyl, -CH2OH, -CH2NH2, and -CH2CH2N(CH3)2. In certain embodiments, R31 is selected from oxo, hydrogen, fluorine, cyano, -NH2, -CH2OH, -CH2NH2, methyl, trifluoromethyl, and -O-methyl. In certain embodiments, R31 is selected from hydrogen, -NH2, -CH2OH, and -CH2NH2. In certain embodiments, R31 is hydrogen. In certain embodiments, ring A is selected from phenylene, naphthylene, and -(5-10 membered)heteroarylene-, wherein the phenylene, naphthylene, and -(5-10 membered)heteroarylene are optionally substituted with one or more R31, wherein R31 is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, ring A is selected from -(5-9 membered)heteroarylene-, wherein the -(59 membered)heteroarylene- is optionally substituted with 1, 2, 3, or 4 R31, wherein R31 is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, ring A is selected from -(5-6 membered)heteroarylene-, wherein the -(56 membered)heteroarylene- is optionally substituted with 1, 2, 3, or 4 R31, wherein R31 is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, ring A is selected from oxazolylene, isoxazolylene, thiazolylene, isothiazolylene, pyrazolylene, imidazolylene, triazolylene, tetrazolylene, pyridinylene, pyrazinylene, pyridazinylene, pyrimidinylene, pyridazinoimidazolylene, pyrazinoimidazolylene, and pyrimidinonylene; for example, ring A is selected from oxazolylene, imidazolylene, or pyrimidinylene; for example, ring A is selected from oxazolylene; ring A is optionally substituted with 1, 2, or 3 R31, wherein R31 is defined as described in any one of the embodiments of the present disclosure. * In certain embodiments, ring A is selected from N-N , and ' N , wherein the * end is attached to T.For example, ring A is In certain embodiments, ring A is selected from and wherein the * end is attached to T. In certain embodiments, ring A is selected from wherein the * end is attached to T. For example, ring A is selected from In certain embodiments,R1 is selected from hydrogen, halogen, cyano, -OH, -(C1-C4)alkyl, and -O-(C1-C4)alkyl. In certain embodiments, R1 is selected from hydrogen, fluorine, chlorine, cyano, -OH, methyl, ethyl, propyl, -O-methyl, -O-ethyl, and -O-propyl. In certain embodiments, R1 is selected from hydrogen and -O-methyl. In certain embodiments, R1 is -O-methyl. In certain embodiments, X1 is selected from N, CH, and C(OCH3). In certain embodiments, X1 is selected from N and C(OCH3). In certain embodiments, X1 is selected from C(OCH3). In certain embodiments, X1 is selected from N. In certain embodiments,R2 is selected from hydrogen, halogen, cyano, -OH, -(C1-C4)alkyl, and -O-(C1-C4)alkyl. In certain embodiments, R2 is selected from hydrogen, fluorine, chlorine, cyano, -OH, methyl, ethyl, propyl, -O-methyl, -O-ethyl, and -O-propyl. In certain embodiments, R2 is hydrogen. In certain embodiments, X2 is selected from N and CH. In certain embodiments, X2 is C(R2). In certain embodiments, X2 is selected from CH. In certain embodiments,R3 is selected from -(C3-C6)cycloalkyl, -(4-6 membered)heterocyclyl, -(C6-C10)aryl, and -(5-12 membered)heteroaryl, wherein the -(C3-C6)cycloalkyl, -(4-6 membered)heterocyclyl, -(C6-C10)aryl, and -(5-12 membered)heteroaryl are optionally substituted with one or more R31. In certain embodiments, theR31 is selected from oxo, hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C4)alkyl, -(C1-C4)alkylene-OH, -(C1-C4)alkylene-NH2, -(C1-C4)alkylene-NH(C1-C4)alkyl, -(C1-C4)alkylene-N[(C1-C4)alkyl]2, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl,      -(4-8 membered)heterocyclyl,      -O-(C3-C6)cycloalkyl,      -O-(4-8 membered)heterocyclyl, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C4)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2, -C(=O)-NH(C1-C4)alkyl, and -C(=O)-N[(C1-C4)alkyl]2. In certain embodiments, R31 is selected from oxo, hydrogen, halogen, cyano, -OH, -SH, -NH2, -(C1-C4)alkyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -NH-(C1-C4)alkyl, -(C1-C4)alkylene-OH, -(C1-C4)alkylene-NH2, -(C1-C4)alkylene-NH(C1-C4)alkyl, and -(C1-C4)alkylene-N[(C1-C4)alkyl]2. In certain embodiments, R31 is selected from oxo, hydrogen, fluorine, chlorine, cyano, -OH, -SH, -NH2, methyl, halomethyl, -O-methyl, -CH2OH, -CH2NH2, and -CH2CH2N(CH3)2. In certain embodiments, R31 is selected from oxo, hydrogen, fluorine, cyano, -NH2, -CH2OH, -CH2NH2, methyl, trifluoromethyl, and -O-methyl. In certain embodiments, R31 is selected from hydrogen, -NH2, -CH2OH, and -CH2NH2. In certain embodiments, R31 is selected from hydrogen. In certain embodiments, R3 is selected from -(C3-C6)cycloalkyl and -(4-6 membered)heterocyclyl, wherein the -(C3-C6)cycloalkyl and -(4-6 membered)heterocyclyl are optionally substituted with one or more R31, wherein R31 is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R3 is selected from cyclopropyl, oxetanyl, tetrahydrofuranyl, azetidinyl, pyrrolidinyl, morpholinyl, morpholinonyl, piperidinyl, piperazinyl, and piperazinonyl, wherein the cyclopropyl, oxetanyl, tetrahydrofuranyl, azetidinyl, pyrrolidinyl, morpholinyl, morpholinonyl, piperidinyl, piperazinyl, and piperazinonyl are optionally substituted with 1, 2, or 3 R31, wherein R31 is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R3 is selected from 0 O , and In certain embodiments, R3 is selected from phenyl, naphthyl, and -(5-10 membered)heteroaryl, wherein the phenyl, naphthyl, and -(5-10 membered)heteroaryl are optionally substituted with one or more R31, wherein R31 is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R3 is selected from -(5-9 membered)heteroaryl, wherein the -(5-9 membered)heteroaryl is optionally substituted with 1, 2, 3, or 4 R31, wherein R31 is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R3 is selected from oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyrazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrazinyl, pyridazinyl, pyrimidinyl, pyridazinoimidazolyl, pyrazinoimidazolyl, and pyrimidinonyl; for example, R3 is selected from oxazolyl, imidazolyl, or pyrimidinyl; for example, R3 is selected from oxazolyl; R3 is optionally substituted with 1, 2, or 3 R31, wherein R31 is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R3 is selected from NA I , N and , , , , , , 'O , wherein the , , , , and '0 are optionally substituted with 1, 2, or 3 R31, wherein R31 is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R3 is selected from is optionally substituted with 1, 2, or 3 R31. and wherein R3 In certain embodiments, R3 is selected from H2N 10 In certain embodiments, R3 is selected from HO MeO . . , ■ k, »3 ■ ,,. f CH nc In certain embodiments, R3 is selected from N , H2N [°H In certain embodiments, R3 is selected from N HO H2N ,, h2n 10 . , MeO Oh Cu CVh jO ncO \=N   . N=N . \=N   . f , and In certain embodiments, R3 is selected from , , , , , , MeO , and o In certain embodiments, R3 is selected from In certain embodiments, R3 is selected from In certain embodiments, R4 is selected from hydrogen, halogen, cyano, -OH, -NH2, -(C1-C4)alkyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, and -O-(C1-C4)haloalkyl. In certain embodiments, R4 is selected from hydrogen, fluorine, chlorine, cyano, -OH, -NH2, and methyl. In certain embodiments, R4 is hydrogen. In certain embodiments, X is selected from O, S, NH, N[(C1-C4)alkyl], N[C(=O)-Rc], C(Ra)(Rb), C(=O), C[=C(Ra)Rb], S(=O), and S(=O)2, wherein Ra and Rb are each independently selected from hydrogen, halogen, cyano, -ORc, -SRc, -N(Rc)Rc, -(C1-C4)alkyl, and -(C1-C4)haloalkyl, wherein Rc is selected from hydrogen, -(C1-C4)alkyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, and -(C3-C6)cycloalkyl. In certain embodiments, Rc is selected from hydrogen, methyl, ethyl, halomethyl, -O-methyl, and cyclopropyl. In certain embodiments, Ra and Rb are each independently selected from hydrogen, fluorine, chlorine, cyano, -OH, -O-methyl, -SH, -S-methyl, -NH2, -N(methyl)2, -N(methyl)-ethyl, -N(ethyl)2, methyl, ethyl, propyl, halomethyl, haloethyl, and halopropyl. In certain embodiments, X is selected from O, S, NH, and N[(C1-C4)alkyl]. In certain embodiments, X is selected from O, S, and NH. In certain embodiments, X is selected from O and S. In certain embodiments, X is selected from O. In certain embodiments, ring B is selected from -(C6-C10)aryl and (5-10 membered)heteroaryl. In certain embodiments, ring B is selected from phenyl, naphthyl, and (5-6 membered)heteroaryl. In certain embodiments, the structural unit In certain embodiments, R5 and R6 are each independently selected from hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1- C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, and -O-(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, and -O-(4-8 membered)heterocyclyl are optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and N[(C1-C4)alkyl]2. In certain embodiments, R5 and R6 are each independently selected from hydrogen, halogen, cyano, -OH, -NH2, -(C1-C4)alkyl, -(C1-C4)alkyl-OH, -(C1-C4)alkyl-NH2, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, and -(C3-C6)cycloalkyl. In certain embodiments, R5 is selected from hydrogen, fluorine, chlorine, bromine, cyano, -OH, -NH2, and -CH2NH2. In certain embodiments, R5 is selected from hydrogen, -OH, -NH2, and -CH2NH2. In certain embodiments, R5 is selected from hydrogen. In certain embodiments, R6 is selected from hydrogen, fluorine, chlorine, bromine, cyano, -OH, -NH2, -O-methyl, and cyclopropyl. In certain embodiments, R6 is selected from hydrogen, fluorine, chlorine, bromine, cyano, -OH, -NH2, and -O-methyl. In certain embodiments, R6 is selected from hydrogen, cyano, and -O-methyl. In certain embodiments, R6 is selected from cyano and -O-methyl. In certain embodiments, R6 is cyano. In certain embodiments, R5 and R6, together with the atoms to which they are attached, form * o ' , wherein * indicates the position of the attached atom. In certain embodiments, ring C is selected from -(C6-C10)aryl and (5-10 membered)heteroaryl. In certain embodiments, ring C is selected from phenyl, naphthyl, and (5-6 membered)heteroaryl. In certain embodiments, the structural unit In certain embodiments, the structural unit In certain embodiments, each R7 is independently selected from hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl,      -(4-8 membered)heterocyclyl,      -O-(C3-C6)cycloalkyl,      -O-(4-8 membered)heterocyclyl, and -NHC(=O)-(C1-C4)alkyl, wherein the -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-8 membered)heterocyclyl, and -NHC(=O)-(C1-C4)alkyl are optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2. In certain embodiments, each R7 is independently selected from hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, and -O-(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, and -O-(4-8 membered)heterocyclyl are optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2. In certain embodiments, each R7 is independently selected from hydrogen, halogen, cyano, -OH, -NH2, -(C1-C4)alkylene-OH, -(C1-C4)alkylene-NH(C1-C4)alkyl, -(C1-C4)alkylene-N[(C1-C4)alkyl]2, -(C1-C4)alkylene-NH2, and -NHC(=O)-(C1-C4)alkylene-NH2. In certain embodiments, each R7 is independently selected from hydrogen, halogen, cyano, -OH, -NH2, -(C1-C4)alkylene-OH, -(C1-C4)alkylene-NH(C1-C4)alkyl, -(C1-C4)alkylene-N[(C1-C4)alkyl]2, and -(C1-C4)alkylene-NH2. In certain embodiments, each R7 is independently selected from hydrogen, fluorine, chlorine, bromine, -OH, -NH2, -CH2OH, -CH2NH2, -NHC(=O)CH2NH2, and -NHC(=O)CH2CH2NH2. In certain embodiments, each R7 is independently selected from hydrogen, fluorine, chlorine, bromine, -OH, -NH2, -CH2OH, and -CH2NH2. In certain embodiments, each R7 is independently selected from hydrogen. In certain embodiments, m is 1, 2, or 3. In certain embodiments, m is 1. In certain embodiments, R8a, R8b, R9a, and R9b are each independently selected from hydrogen, halogen, cyano, -(C1-C4)alkyl, -(C1-C4)haloalkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -OR, -N(R)R, -[(C1-C6)alkylene]R,       -[(C1-C6)alkylene]OR,       -[(C1-C6)alkylene]N(R)R,       -[(C1- C6)alkylene]N(R)C(=O)R, -[(C1-C6)alkylene]N(R)C(=O)N(R)R, -C(=O)R, -C(=O)N(R)R, -C(=O)[(C1-C6)alkylene]N(R)R, -C(=O)OR, -C(=S)N(R)R, -SR, -S(=O)R, -S(=O)2R, -S(=O)2N(R)R, -N(R)C(=O)R, -N(R)C(=O)N(R)R, and -P(=O)(OR)(OR), wherein each R is independently selected from hydrogen, -OH, -NH2, -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -(C1-C4)alkylene-O-(C1-C4)alkyl,     -S-(C1-C4)alkyl,     -S(=O)2     -(C1-C4)alkyl,     -(C3-C6)cycloalkyl,     -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-8 membered)heterocyclyl, -C(=O)-H, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C4)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2, -C(=O)-NH(C1-C4)alkyl, -[(C1-C4)alkylene]-(C3-C6)cycloalkyl, -C(=O)-N[(C1-C4)alkyl]2, -[(C1-C4)alkylene]-(4-8 membered)heterocyclyl, -(C6-C10)aryl, -[(C1-C4)alkylene]-(C6-C10)aryl, and -(5-10 membered)heteroaryl; the -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -(C1-C4)alkylene-O-(C1-C4)alkyl,     -S-(C1-C4)alkyl,     -S(=O)2-(C1-C4)alkyl,     -(C3-C6)cycloalkyl,     -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-8 membered)heterocyclyl, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C4)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH(C1-C4)alkyl, -[(C1-C4)alkylene]-(C3-C6)cycloalkyl, -C(=O)-N[(C1-C4)alkyl]2, -[(C1-C4)alkylene]-(4-8 membered)heterocyclyl, -(C6-C10)aryl, -[(C1-C4)alkylene]-(C6-C10)aryl, and -(5-10 membered)heteroaryl are optionally substituted with 1, 2, 3, 4, 5, 6, or 7 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, N[(C1-C4)alkyl]2, and (C1-C4)alkyl. In certain embodiments, R8a, R8b, R9a, and R9b are each independently selected from hydrogen, halogen, cyano, -(C1-C4)alkyl, -(C1-C4)haloalkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -OR, -N(R)R, -[(C1-C6)alkylene]R, -[(C1-C6)alkylene]OR, -[(C1-C6)alkylene]N(R)R, -C(=O)R, -C(=O)N(R)R, -C(=O)[(C1-C6)alkylene]N(R)R, -C(=O)OR, -C(=S)N(R)R, -SR, -S(=O)R, -S(=O)2R, -S(=O)2N(R)R, -N(R)C(=O)R, -N(R)C(=O)N(R)R, and -P(=O)(OR)(OR); each R is independently selected from hydrogen, -OH, -NH2, -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-8 membered)heterocyclyl, -C(=O)-H, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C4)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2,   -C(=O)-NH(C1-C4)alkyl, -C(=O)-N[(C1-C4)alkyl]2,   -[(C1- C4)alkylene]-(4-8 membered)heterocyclyl, -(C6-C10)aryl, -[(C1-C4)alkylene]-(C6-C10)aryl, and -(5-10 membered)heteroaryl, wherein the -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-8 membered)heterocyclyl, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C4)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH(C1-C4)alkyl,            -C(=O)-N[(C1-C4)alkyl]2,            -[(C1-C4)alkylene]-(4-8 membered)heterocyclyl, -(C6-C10)aryl, -[(C1-C4)alkylene]-(C6-C10)aryl, and -(5-10 membered)heteroaryl are optionally substituted with 1, 2, 3, 4, 5, 6, or 7 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and N[(C1-C4)alkyl]2. In certain embodiments, each R is independently selected from hydrogen, -OH, -NH2, -(C1-C4)alkyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -(C1-C4)alkylene-O-(C1-C6)alkyl, -O-(C1-C4)haloalkyl, -S(=O)2-(C1-C4)alkyl, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -C(=O)-H, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, -[(C1-C4)alkylene]-(C3-C6)cycloalkyl, and -[(C1-C4)alkylene]-(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -(C1-C4)alkylene-O-(C1-C6)alkyl, -O-(C1-C4)haloalkyl, -S(=O)2-(C1-C4)alkyl, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, -[(C1-C4)alkylene]-(C3-C6)cycloalkyl, and -[(C1-C4)alkylene]-(4-8 membered)heterocyclyl are optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, N[(C1-C4)alkyl]2, methyl, and ethyl. In certain embodiments, each R is independently selected from hydrogen, -OH, -NH2, -(C1-C4)alkyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -C(=O)-H, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, and -[(C1-C4)alkylene]-(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, and -[(C1-C4)alkylene]-(4-8 membered)heterocyclyl are optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and N[(C1-C4)alkyl]2. In certain embodiments, each R is independently selected from hydrogen, -OH, -NH2, -CH3, -CH2CH3, -CH2OH, -CH2CH2OH, -CH2OCH3, -CH2NH2, -CH2CH2NH2, -CH2CH2NHCH3, -CH2N(CH3)2, -CH(N(CH3)2)CH2OH, -CH2OCH2CH2OH, -OCH3, -C(=O)-H, -C(=O)CH3, -C(=O)CH2OH, -S(=O)2CH3, cyclobutyl-OH, oxetanyl, azetidinyl, azetidinyl-OH, pyrrolidinyl, piperazinyl, azetidinyl-CH3, piperazinyl-CH3, and -CH2-azetidinyl. In certain embodiments, each R is independently selected from hydrogen, -OH, -NH2, -CH3, -CH2OH, -CH2CH2OH, -CH2NH2, -CH2CH2NH2, -OCH3, -C(=O)-H, -C(=O)CH2OH, oxetanyl, azetidinyl, and azetidinyl-OH. In certain embodiments, each R is independently selected from hydrogen, -OH, -NH2, -(C1-C4)alkyl, -O-(C1-C4)alkyl, and -(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl, -O-(C1-C4)alkyl, and -(4-8 membered)heterocyclyl are optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -NH2, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, and -O-(C1-C4)alkyl. In certain embodiments, each R is independently selected from hydrogen, -OH, -(C1-C4)alkyl, -O-(C1-C4)alkyl, and -(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl, -O-(C1-C4)alkyl, and -(4-8 membered)heterocyclyl are optionally substituted with 1, 2, or 3 groups selected from hydrogen, halogen, -OH, -NH2, -NH-methyl, and -N(methyl)2. In certain embodiments, each R is independently selected from methyl, ethyl, propyl, -O-methyl, -O-ethyl, -O-propyl, oxetanyl, and azetidinyl, wherein the aforementioned groups are each independently and optionally substituted with 1, 2, or 3 groups selected from -OH and -NH2. In certain embodiments, R8a, R8b, R9a, and R9b are each independently selected from hydrogen, cyano, -OR, -N(R)R, -[(C1-C4)alkylene]R, -[(C1-C4)alkylene]OR, -[(C1-C4)alkylene]N(R)R, -[(C1-C4)alkylene]N(R)C(=O)R, -[(C1-C4)alkylene]N(R)C(=O)N(R)R, -C(=O)R, -C(=O)N(R)R, -C(=O)[(C1-C4)alkylene]N(R)R, -C(=O)OR, -C(=S)N(R)R, -S(=O)R, -S(=O)2R, -S(=O)2N(R)R, -N(R)C(=O)R, and -N(R)C(=O)N(R)R, wherein R is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R8a, R8b, R9a, and R9b are each independently selected from hydrogen, -OR, -N(R)R, -[(C1-C4)alkylene]R, -[(C1-C4)alkylene]OR, -[(C1-C4)alkylene]N(R)R, -C(=O)R, -C(=O)N(R)R, -C(=O)[(C1-C4)alkylene]N(R)R, -C(=O)OR, -C(=S)N(R)R, -S(=O)R, -S(=O)2R, -S(=O)2N(R)R, -N(R)C(=O)R, and -N(R)C(=O)N(R)R, wherein R is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R8a and R8b are each independently selected from hydrogen, -methylene-R, -ethylene-R, -propylene-R, -methylene-OR, -ethylene-OR, -propylene-OR, -methylene-N(R)R, -ethylene-N(R)R, -propylene-N(R)R, -C(=O)R, -C(=O)N(R)R, and -C(=O)OR, wherein R is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R8a and R8b are each independently selected from hydrogen, -methylene-R, -methylene-OR, -methylene-N(R)R, -C(=O)R, -C(=O)OR, and -C(=O)N(R)R, wherein R is defined as described in any one of the embodiments of the present disclosure; for example, each R is independently selected from hydrogen, -OH, -NH2, -(C1-C4)alkyl, -O-(C1-C4)alkyl, -C(=O)-(C1-C4)alkyl, -S(=O)2(C1-C4)alkyl, and -(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl and -(4-8 membered)heterocyclyl are each optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -NH2, -NHCH3, and CH3. In certain embodiments, R8a and R8b are each independently selected from hydrogen, -methylene-R, -methylene-OR, -methylene-N(R)R, -C(=O)R, -C(=O)OR, and -C(=O)N(R)R, wherein R is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R8a is hydrogen. In certain embodiments, R8a is In certain embodiments, R8b is selected from hydrogen, and In certain embodiments, R8b is selected from hydrogen, 5 X^''^NHMe In certain embodiments, R8b is selected from hydrogen, \^oh 10 and In certain embodiments, R8b is selected from hydrogen, and In certain embodiments, each R8b is independently selected from hydrogen, -methylene-R, - methylene-OR, -methylene-N(R)R, and -C(=O)N(R)R, wherein each R is independently selected from hydrogen, -(C1-C4)alkyl, and -O-(C1-C4)alkyl. In certain embodiments, R8b is selected from hydrogen, Y'^NEt2 and In certain embodiments, R8b is selected from hydrogen, and In certain embodiments, R8b is selected from hydrogen, and In certain embodiments, R8b is selected from hydrogen, and In certain embodiments, R9a and R9b are each independently selected from hydrogen, -CN, -OR, - NHR, -N(R)R, -NHC(=O)R, -methylene-R, -ethylene-R, -propylene-R, -methylene-N(R)R, - ethylene-N(R)R, -propylene-N(R)R, -methylene-NHC(=O)R, and -methylene-NHC(=O)NHR, wherein R is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R9a and R9b are each independently selected from hydrogen, -OR, -NHR, -methylene-R, -ethylene-R, -propylene-R, -methylene-N(R)R, -ethylene-N(R)R, -propylene-N(R)R, and -NHC(=O)R, wherein R is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R9a and R9b are each independently selected from hydrogen, -CN, -OR, - N(R)R, -NHC(=O)R, -methylene-N(R)R, -methylene-NHC(=O)R, and -methylene-NHC(=O)NHR, wherein R is defined as described in any one of the embodiments of the present disclosure; for example, each R is independently selected from hydrogen, -OH, -(C1-C4)alkyl, -(C1-C4)alkylene-O-(C1-C4)alkyl,      -S(=O)2(C1-C4)alkyl,      -(C3-C6)cycloalkyl,      -(4-8 membered)heterocyclyl,       -methylene-(C3-C6)cycloalkyl,       and -methylene-(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl, -(C3-C6)cycloalkyl, and -(4-8 membered)heterocyclyl are each optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -NH2, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -O-(C1-C4)alkyl, and -(C1-C4)alkyl. In certain embodiments, R9a and R9b are each independently selected from hydrogen, -OR, -N(R)R, -methylene-N(R)R, and -NHC(=O)R, wherein R is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R9a is selected from hydrogen, -CN, -N(R)R, -NHC(=O)R, -methylene-N(R)R, -methylene-NHC(=O)R, and -methylene-NHC(=O)NHR, wherein R is defined as described in any one of the embodiments of the present disclosure; for example, each R is independently selected from hydrogen, -OH, methyl, ethyl, -methylene-O-ethyl, -S(=O)2-methyl, cyclobutyl, azetidinyl, -methylene-cyclobutyl, and -methylene-azetidinyl, wherein the aforementioned groups are each independently and optionally substituted with 1, 2, or 3 groups selected from -OH, OCH3, NHCH3, N(CH3)2, and CH3. In certain embodiments, R9a is selected from hydrogen and -methylene-N(R)R, wherein R is defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R9a is selected from hydrogen, -CN, -NHCH3, -N(CH3)2, -NHC(=O)H, -NHC(=O)CH2OH, -NHC(=O)CH2OCH3, -NHC(=O)CH2NHCH3, -NHC(=O)CH2N(CH3)2, -CH2NH2, -CH2NHCH3, -CH2N(CH3)2, -CH2N(CH2CH3)2, -CH2N(CH3)(CH2CH3), -CH2NHC(=O)CH2OH,     -CH2NHC(=O)CH2OCH3,     -CH2NHC(=O)CH2NHCH3,     - CH2NHC(=O)CH2N(CH3)2, -CH2NHC(=O)H, -CH2NHC(=O)CH3, -CH2NHC(=O)NHOH, -CH2NHC(=O)NHCH2CH2OH, -CH2NHC(=O)CH(N(CH3)2)CH2OH, -CH2NHC(=O)CH2NHCH3, -CH2NHC(=O)CH2N(CH3)2, -CH2NHC(=O)CH2N(CH2CH3)2, -CH2NHC(=O)CH2OCH2CH2OH, -CH2NHS(=O)2CH3, -CH2NHC(=O)cyclobutyl-OH, -CH2NHC(=O)-azetidinyl-CH3, and -CH2NHC(=O)CH2-azetidinyl. In certain embodiments, R9a is selected from hydrogen, -CH2NH2, -CH2NHCH3, -NHC(=O)H, -NHC(=O)CH2OH, and -CH2NHC(=O)CH2OH. / K^0H NC "N HN       HN In certain embodiments, R9a is selected from hydrogen, -^, -^,            ,           , 10 0 , H O OH noh OH OH . N-- / OH In certain embodiments, R9a is selected from hydrogen, N NC NZ In certain embodiments, R9a is selected from hydrogen, NC O In certain embodiments, R9a is selected from hydrogen, -CN, -methylene-N(R)R, and -methylene- NHC(=O)R, wherein each R is independently selected from hydrogen, -(C1-C4)alkyl, -methylene- O-(C1-C4)alkyl, -methylene-NH-(C1-C4)alkyl, -methylene-N[(C1-C4)alkyl]2, and -S(=O)2-(C1- C4)alkyl. NC In certain embodiments, R9a is selected from hydrogen, and In certain embodiments, R9a is selected from hydrogen, In certain embodiments, R9a is selected from hydrogen, In certain embodiments, R9a is selected from hydrogen, and In certain embodiments, R9a is selected from hydrogen, In certain embodiments, R9a is hydrogen. 10 In certain embodiments, R9a is HQ In certain embodiments, R9b is selected from hydrogen and In certain embodiments, R9b is -OH. HQ In certain embodiments, R9b is      . NC In certain embodiments, R9b is selected from hydrogen, > , and In certain embodiments, R8a, R8b, and R9a are hydrogen, and R9b is as described in any one of the embodiments of the present disclosure. In certain embodiments, R8a, R8b, and R9b are hydrogen, and R9a is as described in any one of the embodiments of the present disclosure. In certain embodiments, R8a and R9a are hydrogen, R8b and R9b are as described in any one of the embodiments of the present disclosure, and neither R8b nor R9b is hydrogen. In certain embodiments, R8a and R8b, and R9a and R9b are independently combined to form oxo, -(C2-C4)alkenyl, -(C3-C6)cycloalkyl, or -(4-8 membered)heterocyclyl. In certain embodiments, R8a and R8b are combined to form oxo, -(C2-C4)alkenyl, -(C3-C6)cycloalkyl, or -(4-8 membered)heterocyclyl. In certain embodiments, R9a and R9b are combined to form oxo, -(C2-C4)alkenyl, -(C3-C6)cycloalkyl, or -(4-8 membered)heterocyclyl. In certain embodiments, R8a and R8b, and R9a and R9b are independently combined to form oxo, vinyl, propenyl, cyclopropyl, cyclobutyl, cyclopentyl, oxetanyl, tetrahydrofuranyl, tetrahydropyranyl, azetidinyl, pyrrolidinyl, piperidinyl, or piperazinyl. In certain embodiments, R8a and R9a, together with the carbon atoms to which they are attached, form (C3-C6)cycloalkyl, (4-8 membered)heterocyclyl, or (5-9 membered)heteroaryl, wherein the aforementioned group is optionally substituted with 1, 2, 3, 4, 5, 6, or 7 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, and -(C6-C10)aryl. In certain embodiments, R8b and R9b, together with the carbon atoms to which they are attached, form (C3-C6)cycloalkyl, (4-8 membered)heterocyclyl, or (5-9 membered)heteroaryl, wherein the aforementioned group is optionally substituted with 1, 2, 3, 4, 5, 6, or 7 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, and -(C6-C10)aryl. In certain embodiments, R8a and R9a, and R8b and R9b, together with the carbon atoms to which they are attached, form (C3-C6)cycloalkyl, (4-8 membered)heterocyclyl, or (5-9 membered)heteroaryl, wherein the aforementioned group is optionally substituted with 1, 2, 3, 4, 5, 6, or 7 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, and -(C6-C10)aryl. In certain embodiments, R8a and R9a, together with the carbon atoms to which they are attached, form (4-8 membered)heterocyclyl or (5-9 membered)heteroaryl, wherein the aforementioned group is optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, fluorine, chlorine, -OH, -O-methyl, -O-ethyl, -NH2, -NH-methyl, -NH-ethyl, -N(methyl)2, -N(methyl)-ethyl, -N(ethyl)2, cyclopropyl, cyclobutyl, cyclopentyl, phenyl, and naphthyl. In certain embodiments, R8b and R9b, together with the carbon atoms to which they are attached, form (4-8 membered)heterocyclyl or (5-9 membered)heteroaryl, wherein the aforementioned group is optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, fluorine, chlorine, -OH, -O-methyl, -O-ethyl, -NH2, -NH-methyl, -NH-ethyl, -N(methyl)2, -N(methyl)-ethyl, -N(ethyl)2, cyclopropyl, cyclobutyl, cyclopentyl, phenyl, and naphthyl. In certain embodiments, R8a and R9a, and R8b and R9b, together with the carbon atoms to which they are attached, form (4-8 membered)heterocyclyl or (5-9 membered)heteroaryl, wherein the aforementioned group is optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, fluorine, chlorine, -OH, -O-methyl, -O-ethyl, -NH2, -NH-methyl, -NH-ethyl, -N(methyl)2, -N(methyl)-ethyl, -N(ethyl)2, cyclopropyl, cyclobutyl, cyclopentyl, phenyl, and naphthyl. In certain embodiments, R8a and R9a, together with the carbon atoms to which they are attached, form (4-8 membered)heterocyclyl or (5-9 membered)heteroaryl, wherein the aforementioned group is optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, fluorine, chlorine, -OH, -O-methyl, -O-ethyl, -NH2, -NH-methyl, -NH-ethyl, -N(methyl)2, -N(methyl)-ethyl, -N(ethyl)2, cyclopropyl, cyclobutyl, cyclopentyl, phenyl, and naphthyl. In certain embodiments, R8b and R9b, together with the carbon atoms to which they are attached, form (4-8 membered)heterocyclyl or (5-9 membered)heteroaryl, wherein the aforementioned group is optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, fluorine, chlorine, -OH, -O-methyl, -O-ethyl, -NH2, -NH-methyl, -NH-ethyl, -N(methyl)2, -N(methyl)-ethyl, -N(ethyl)2, cyclopropyl, cyclobutyl, cyclopentyl, phenyl, and naphthyl. In certain embodiments, R8a and R9a are absent, and R8b and R9b, together with the atoms to which o they are attached, form            , wherein * indicates the position of the attached atom. In certain embodiments, R10 is selected from -OH. In certain embodiments, R10 and R9a, together with the atoms to which they are attached, form 5membered nitrogen-containing heterocyclyl, wherein the 5-membered nitrogen-containing heterocyclyl is optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2. In certain embodiments, R10 and R9a, together with the atoms to which they are attached, form imidazolinyl, wherein the imidazolinyl is optionally substituted with 1, 2, or 3 groups selected from halogen, -OH, methyl, -NH2, -NH-methyl, and -N(methyl)2. In certain embodiments, R10 and R9a, together with the atoms to which they are attached, form HN^* * , wherein * indicates the position of the attached atom. In certain embodiments, R10 is -OH. OH In certain embodiments, R10 is . 5 In certain embodiments, the drug group is selected from a structure represented by formula I-A-1, II-A-1', II-A-1, III-A-1', III-A-1, IV-A-1, or V-A-1: 10 wherein X, X1, X2, ring A, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, R12, m, n, M, 15 W, U, Z, Y, L, Q, and T are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the drug group is selected from a structure represented by formula I-A-2, 10 II-A-2', II-A-2, III-A-2', III-A-2, IV-A-2, or V-A-2: II-A-2' III-A-2' wherein X, X1, X2, ring A, R3, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, R12, m, n, M, W, U, Z, Y, L, Q, and T are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the drug group is selected from a structure represented by formula I-A-3, III-A-3', III-A-3, IV-A-3, or V-A-3: I-A-3 III-A-3 5                                                     III-A-3' wherein X, X1, X2, ring A, R3, R4, R5, R6, R7, R8b, R9b, R12, m, M, L, Q, and T are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the drug group is selected from a structure represented by formula I-A-4, 10   II-A-4', II-A-4, III-A-4', III-A-4, IV-A-4, or V-A-4: OH p8b pl       -     lx 7 HO / .? £XVy R4 R5 I-A-4 R12 N-J J III-A-4 R1 hq^ I i \ H(4     ' w z / m—।            । R3'Y^xy<^>^ R4 R5 \,6 R6 II-A-4 iHC\ xb ...... -A                              r5 r6 IV-A-4                      V-A-4 II-A-4'                          III-A-4' wherein X, R1, ring A, R3, R4, R5, R6, R7, R8b, R12, m, n, M, W, U, Z, Y, L, Q, and T are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, provided is a compound of the structure represented by the general formula described above, wherein: M is selected from -NH-, -O-, -(C1-C4)alkylene-O-, and -(C1-C4)alkylene-NH-; n is 0 or 1; W is absent or is selected from -(C1-C4)alkylene, -NH-, and -N[-(C1-C4)alkyl]-; U is selected from    -(C1-C4)alkylene-,    -(C3-C6)cycloalkylene-,    and -(4-6 membered)heterocyclylene-; Z is absent or is selected from -(C1-C4)alkylene-, -(C3-C6)cycloalkylene-, and -(4-6 membered)heterocyclylene-; Y is absent or is selected from -O-, -N(Ry)-, and -N+(Ry)2-, wherein Ry is selected from hydrogen, -(C1-C4)alkyl, and -O(C1-C4)alkyl, or Ry and Z form -(4-6 membered)heterocyclylene-; R12 is selected from hydrogen, -(C1-C4)alkyl, -O-(C1-C4)alkyl, and -(C3-C6)cycloalkyl; L is absent or is selected from -C(=O)-(C1-C4)alkylene-O-, -C(=O)-(C1-C4)alkylene-N(RL)-, and -C(=O)-(C1-C4)alkylene-N+(RL)2-, wherein RL is selected from hydrogen, -(C1-C4)alkyl, and -(C1-C4)haloalkyl; Q is selected from -NH-, -O-, -(C1-C4)alkylene-O-, and -(C1-C4)alkylene-NH-; T is selected from -NH-, -O-, -(C1-C4)alkylene-O-, and -(C1-C4)alkylene-NH-; X1 is selected from N and C(R1), wherein R1 is selected from hydrogen, halogen, cyano, -OH, -(C1-C4)alkyl, and -O-(C1-C4)alkyl; X2 is selected from C(R2), wherein R2 is selected from hydrogen, halogen, cyano, -OH, -(C1-C4)alkyl, and -O-(C1-C4)alkyl; R31 is selected from oxo, hydrogen, fluorine, chlorine, cyano, -OH, -SH, -NH2, -(C1-C4)alkyl, -O-(C1-C4)alkyl, -(C1-C4)alkylene-OH, -(C1-C4)haloalkyl, -(C1-C4)alkylene-NH2, -(C1-C4)alkylene-NH(C1-C4)alkyl, and -(C1-C4)alkylene-N[(C1-C4)alkyl]2; R3 is selected from -(5-9 membered)heteroaryl,   -(C3-C6)cycloalkyl,   and -(4-6 membered)heterocyclyl, and R3 is optionally substituted with 1, 2, 3, or 4 R31; ring A is selected from -(5-9 membered)heteroarylene-, and ring A is optionally substituted with 1, 2, 3, or 4 R31; R4 is selected from hydrogen, fluorine, chlorine, cyano, -OH, -NH2, methyl, halomethyl, -O-methyl, -NH-methyl, and cyclopropyl; X is selected from O, S, NH, and N[(C1-C4)alkyl]; ring B is phenyl or phenylene, wherein the phenylene is optionally substituted with 1 R5 or R6; R5 and R6 are each independently selected from hydrogen, fluorine, chlorine, bromine, cyano, -OH, -NH2, -(C1-C4)alkyl, -(C1-C4)alkyl-OH, -(C1-C4)alkyl-NH2, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, and -(C3-C6)cycloalkyl; or R5 and R6, together with the atoms to * , 0    1 which they are attached, form \-"u , wherein * indicates the position of the attached atom; ring C is phenyl or phenylene, wherein the phenylene is optionally substituted with 1 R7; each R7 is independently selected from hydrogen, fluorine, chlorine, bromine, cyano, -OH, -NH2, -(C1-C4)alkylene-OH, -(C1-C4)alkylene-NH(C1-C4)alkyl, -(C1-C4)alkylene-N[(C1-C4)alkyl]2, and -(C1-C4)alkylene-NH2; m is 1, 2, or 3; each R is independently selected from hydrogen, -OH, NH2, -(C1-C4)alkyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -C(=O)-H, -C(=O)-(C1-C4)alkyl,       -C(=O)-(C3-C6)cycloalkyl,       and       -[(C1-C4)alkylene]-(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, and -[(C1-C4)alkylene]-(4-8 membered)heterocyclyl are optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -O-methyl, -O-ethyl, -O-propyl, -NH2, -NH-methyl, -NH-ethyl, -NH-propyl, -N(methyl)2, -N(methyl)-ethyl, -N(methyl)-propyl, -N(ethyl)2, -N(ethyl)-propyl, methyl, and ethyl; zH R8a is \   ; R8b is selected from hydrogen, -methylene-R, -ethylene-R, -propylene-R, -methylene-OR, -ethylene-OR, -propylene-OR, -methylene-N(R)R, -ethylene-N(R)R, -propylene-N(R)R, -C(=O)R, -C(=O)N(R)R, and -C(=O)OR; R9a is selected from hydrogen, -OR, -N(R)R, -methylene-N(R)R, -methylene-NHC(=O)R, and -NHC(=O)R; HQ R9b is selected from hydrogen and ; R10 is OH In certain embodiments, provided is a compound of the structure represented by the general formula described above, wherein: M is selected from -NH-, -O-, -CH2O-, and -CH2NH-; n is 0 or 1; the structural unit -W-U-Z-Y- is selected from -N(Rw)-(C1-C6)alkylene-N(Ry)-, -N(Rw)-(C1-C6)alkylene-N+(Ry)2-, -N(Rw)-(C1-C6)alkylene-O-, -(C1-C6)alkylene-N(Ry)-, -(C1-C6)alkylene-N+(Ry)2-, -(C1-C6)alkylene-O-, -(4-6 membered)heterocyclylene-O-, and -(4-6 membered)heterocyclylene-N(Ry)-; R12 is selected from hydrogen and -(C1-C4)alkyl; L is absent or is selected from -C(=O)CH2O-, -C(=O)CH2CH2O-, -C(=O)CH2N(RL)-, -C(=O)CH2CH2N(RL)-, -C(=O)CH2N+(RL)2-, and -C(=O)CH2CH2N+(RL)2-, wherein RL is selected from hydrogen, methyl, and ethyl; Q is selected from -NH-, -O-, -CH2O-, and -CH2NH-; T is selected from -NH-, -O-, -CH2O-, and -CH2NH-; X1 is selected from N and C(R1), wherein R1 is selected from hydrogen, fluorine, chlorine, cyano, -OH, methyl, ethyl, propyl, -O-methyl, -O-ethyl, and -O-propyl; X2 is selected from C(R2), wherein R2 is selected from hydrogen, fluorine, chlorine, cyano, -OH, methyl, ethyl, propyl, -O-methyl, -O-ethyl, and -O-propyl; R31 is selected from oxo, hydrogen, fluorine, chlorine, cyano, -OH, -SH, -NH2, methyl, halomethyl, -O-methyl, -CH2OH, -CH2NH2, and -CH2CH2N(CH3)2; R3 is selected from cyclopropyl, oxetanyl, morpholinyl, morpholinonyl, piperidinyl, piperazinyl, piperazinonyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyrazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrazinyl, pyridazinyl, pyrimidinyl, pyridazinoimidazolyl, pyrazinoimidazolyl, and pyrimidinonyl, and R3 is optionally substituted with 1, 2, or 3 R31; ring A is selected from oxazolylene, isoxazolylene, thiazolylene, isothiazolylene, pyrazolylene, imidazolylene, triazolylene, tetrazolylene, pyridinylene, pyrazinylene, pyridazinylene, pyrimidinylene, pyridazinoimidazolylene, pyrazinoimidazolylene, and pyrimidinonylene, and ring A is optionally substituted with 1, 2, or 3 R31; R4 is selected from hydrogen, fluorine, chlorine, cyano, -OH, and -NH2; X is selected from O; the structural unit R5 is R5 R6 R5 is selected from hydrogen, -OH, -NH2, and -CH2NH2; R6 is selected from hydrogen, fluorine, chlorine, bromine, cyano, -OH, -NH2, cyclopropyl, and -O-methyl; .5               ................. °'   ,   .        . or R5 and R6, together with the atoms to which they are attached, form X--'"' , wherein * indicates the position of the attached atom; or ring B is         , wherein the * end is attached to Q; the structural unit each R7 is independently selected from hydrogen, fluorine, chlorine, bromine, cyano, -OH, -NH2, -(C1-C4)alkylene-OH, -(C1-C4)alkylene-NH(C1-C4)alkyl, -(C1-C4)alkylene-N[(C1-C4)alkyl]2, and -(C1-C4)alkylene-NH2; m is 1, 2, or 3; / \ * or ring C is              , wherein the * end is attached to M; zH R8a is \   ; R8b is selected from hydrogen, -methylene-R, -methylene-N(R)R, -C(=O)OR, -C(=O)N(R)R, and -C(=O)R, wherein R is defined as described in any one of the embodiments of the present disclosure; for example, each R is independently selected from hydrogen, -OH, methyl, ethyl, -O-methyl, -C(=O)-methyl, -S(=O)2-methyl, azetidinyl, pyrrolidinyl, and piperazinyl, wherein the aforementioned groups are each independently and optionally substituted with 1, 2, or 3 groups selected from -OH and -NH2; R9a is selected from hydrogen, -CN, -N(R)R, -NHC(=O)R, -methylene-N(R)R, -methylene-NHC(=O)R, and -methylene-NHC(=O)NHR, wherein R is defined as described in any one of the embodiments of the present disclosure; for example, each R is independently selected from hydrogen, -OH, methyl, ethyl, -methylene-O-ethyl, -S(=O)2-methyl, cyclobutyl, azetidinyl, -methylene-cyclobutyl, and -methylene-azetidinyl, wherein the aforementioned groups are each independently and optionally substituted with 1, 2, or 3 groups selected from -OH, OCH3, NHCH3, N(CH3)2, and CH3; HQ R9b is selected from hydrogen and      ; OH R10 is In certain embodiments, provided is a compound of the structure represented by the general formula described above, wherein: M is selected from -NH-, -O-, -CH2O-, and -CH2NH-; n is 0 or 1; W is absent or is selected from methylene, ethylene, -NH-, -N(Me)-, and -N(Et)-; U is selected from methylene, ethylene, cyclopropyl, azetidinylene, and pyrrolidinylene; Z is absent or is selected from methylene, ethylene, cyclopropyl, azetidinylene, and pyrrolidinylene; Y is selected from -O-, -N(Ry)-, and -N+(Ry)2-, wherein Ry is selected from hydrogen, methyl, ethyl, and -O-methyl; R12 is selected from hydrogen, methyl, and ethyl; L is absent or is selected from -C(=O)CH2O-, -C(=O)CH2CH2O-, -C(=O)CH2N(RL)-, -C(=O)CH2CH2N(RL)-, -C(=O)CH2N+(RL)2-, and -C(=O)CH2CH2N+(RL)2-, wherein RL is selected from hydrogen, methyl, and ethyl; Q is selected from -NH-; T is selected from -NH-; X1 is C(R1) and N; R1 is selected from hydrogen, fluorine, chlorine, cyano, -OH, methyl, ethyl, propyl, -O-methyl, -O-ethyl, and -O-propyl; X2 is selected from CH; R31 is selected from hydrogen, fluorine, chlorine, cyano, -OH, -SH, -NH2, -CH2OH, -CH2NH2, methyl, trifluoromethyl, and -O-methyl; R3 is selected from 0 , and , , N=N , N ' , and R3 is optionally substituted with 1, 2, or 3 R31; N-N , and ring A is selected from , wherein the * end is attached to T; R4 is hydrogen; X is O; p6 ‘          d6 is K K ; R5 is selected from hydrogen and -NH2; R6 is selected from hydrogen, fluorine, chlorine, bromine, cyano, -OH, -NH2, cyclopropyl, and -O-methyl; * , / ^>1 * 0    ' '■'"'J , wherein * indicates or R5 and R6, together with the atoms to which they are attached, form 10 the position of the attached atom; or ring B is         , wherein the * end is attached to Q; C V(R7)m   Y T XjL 7 the structural unit                      is                or            R'; / .. \ * HlT or ring C is              , wherein the * end is attached to M; each R7 is independently selected from hydrogen, fluorine, chlorine, bromine, -OH, and -NH2; ZH 15   R8a is \ R8b is selected from hydrogen, and R9a is selected from hydrogen, R9b is selected from hydrogen and R10 is In certain embodiments, provided is a compound of the structure represented by the general formula described above, wherein: M is selected from -NH-, -O-, *-CH2O-, and *-CH2NH-, wherein the * end is attached to ring C; n is 0 or 1; W is absent or is selected from -NH- and -N(Me)-; U is selected from methylene, ethylene, and Z is absent; Y is selected from -O-, -NH-, -N(CH3)-, and -N+(CH3)2-; the structural unit -W-U-Z-Y- is selected from *-NH-CH2-CH2-NH-, *-NH-CH2-CH2-O-, *-CH2- * X O-, *-CH2-NH-, *-CH2-N(CH3)-, *-CH2-N+(CH3)2-, and 'o^ , wherein the * end is attached to carbonyl; R12 is selected from hydrogen and methyl; L is absent or is selected from *-C(=O)CH2O-, *-C(=O)CH2N(CH3)-, and *-C(=O)CH2N+(CH3)2-, wherein the * end is attached to N; Q is selected from -NH-; T is selected from -NH-; X1 is selected from C(R1) and N; R1 is selected from -O-methyl; X2 is selected from CH; [ / , R3 is selected from N nC / H ,, and f3c ring A is selected from K'H and         N , wherein the * end is attached to T; R4 is hydrogen; X is O; R6 . is R5 is selected from hydrogen; R6 is selected from cyano and -O-methyl; or R5 and R6, together with the atoms to which they are attached, form , wherein * indicates the position of the attached atom; or ring B is         , wherein the * end is attached to Q; the structural unit R7-; R7 is hydrogen; or ring C is , wherein the * end is attached to M; R8a is R8b is selected from hydrogen, yxoH and NC R9a is hydrogen, HQ R9b is  >-; OH R10 is In certain embodiments, the drug group is selected from a structure represented by formula I-A-5, 10 II-A-5, III-A-5, IV-A-5, or V-A-5: III-A-5 IV-A-5 V-A-5 15 wherein X, R1, ring A, R3, R5, R6, R7, R8b, R9a, R9b, R12, n, M, W, U, Z, Y, L, Q, and T are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, provided is a compound of the structure represented by formula I-A-5, II- A-5, III-A-5, IV-A-5, or V-A-5, wherein: M is selected from -NH-, -O-, *-CH2O-, and *-CH2NH-, wherein the * end is attached to ring C; n is 0 or 1; W is absent or is selected from -NH- and -N(Me)-; U is selected from methylene, ethylene, and ’         «; Z is absent; Y is selected from -O-, -NH-, -N(CH3)-, and -N+(CH3)2-; the structural unit -W-U-Z-Y- is selected from *-NH-CH2-CH2-NH-, *-NH-CH2-CH2-O-, *-CH2- Z \ O-, *-CH2-NH-, *-CH2-N(CH3)-, *-CH2-N+(CH3)2-, and ' o "v , wherein the * end is attached to carbonyl; R12 is selected from hydrogen and methyl; L is absent or is selected from *-C(=O)CH2O-, *-C(=O)CH2N(CH3)-, and *-C(=O)CH2N+(CH3)2-, wherein the * end is attached to N; Q is selected from -NH-; T is selected from -NH-; X is O; R1 is selected from hydrogen, halogen, cyano, -OH, -(C1-C4)alkyl, and -O-(C1-C4)alkyl; in certain embodiments, R1 is selected from hydrogen, fluorine, chlorine, cyano, -OH, methyl, ethyl, propyl, -O-methyl, -O-ethyl, and -O-propyl; R3 is selected from oxazolyl, pyrazolyl, and pyrimidinyl; in certain embodiments, R3 is selected [ o Oh t hh from N , N-y , n , and N , and R3 is optionally substituted with 1, 2, or 3 R31; ring A is selected from -(5-6 membered)heteroarylene-, wherein the -(5-6 membered)heteroarylene- is optionally substituted with 1, 2, 3, or 4 R31; each R31 is independently selected from hydrogen, fluorine, chlorine, cyano, -OH, -SH, -NH2, -CH2OH, -CH2NH2, -CH3, -CF3, and -OCH3; or R3 is selected from N and N lOH or ring A is selected from            ,      \--N   , N , and         N , wherein the * end is attached to T; R5 is hydrogen or -NH2; R6 is selected from hydrogen, fluorine, chlorine, bromine, cyano, -OH, -NH2, cyclopropyl, and -O-methyl; .5            .     .,       ................. O, ।             .              , or R5 and R6, together with the atoms to which they are attached, form v--'-' , wherein * indicates the position of the attached atom; each R7 is independently selected from hydrogen, fluorine, chlorine, bromine, -OH, and -NH2; R8b is selected from hydrogen, -methylene-R, -methylene-OR, -methylene-N(R)R, -C(=O)R, - C(=O)OR, and -C(=O)N(R)R, wherein R is defined as described in any one of the embodiments of the present disclosure; for example, each R is independently selected from hydrogen, -OH, -NH2, -(C1-C4)alkyl, -O-(C1-C4)alkyl, -C(=O)-(C1-C4)alkyl, -S(=O)2(C1-C4)alkyl, and -(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl and -(4-8 membered)heterocyclyl are each optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -NH2, - .                          x' V OH NHCH3, and CH3; in certain embodiments, R8b is selected from hydrogen,         ,^, and R9a is selected from hydrogen, -CN, -N(R)R, -NHC(=O)R, -methylene-N(R)R, -methylene-NHC(=O)R, and -methylene-NHC(=O)NHR, wherein R is defined as described in any one of the embodiments of the present disclosure; for example, each R is independently selected from hydrogen, -OH, methyl, ethyl, -methylene-O-ethyl, -S(=O)2-methyl, cyclobutyl, azetidinyl, -methylene-cyclobutyl, and -methylene-azetidinyl, wherein the aforementioned groups are each independently and optionally substituted with 1, 2, or 3 groups selected from -OH, OCH3, NHCH3, NC '"N N(CH3)2, and CH3; in certain embodiments, R9a is selected from hydrogen, , HQ R9b is selected from hydrogen and In certain embodiments, the drug group is selected from structures represented by formulas I-A-6 and I-A-7: 10 wherein R1, R31, R5, R6, R8b, R9a, R9b, and M are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, R8b and R9a are hydrogen, and R9b is as described in any one of the embodiments of the present disclosure. In certain embodiments, R8b and R9b are hydrogen, and R9a is as described in any one of the 15 embodiments of the present disclosure. In certain embodiments, R9a is hydrogen, R8b and R9b are as described in any one of the embodiments of the present disclosure, and neither R8b nor R9b is hydrogen. In certain embodiments, R31 is hydrogen. In certain embodiments, the drug group is selected from the structures shown in Table A: Table A No. Structure I-A1 fYQjt.NV v° CN I-A12 I-A13 I-A14 I-A15 I-A23 IE o 9 7 Z A 4 / / b ® I-A24 o A ° / =\ / ow / ”° 'r° <\ / / sz A4° b I-A25 FTV^yV Z'A^T o CN I-A26 CH z = / AW'5 o^\,A )—•. z       H0 V-C0 b I-A27 >Xw AXXAzA / N^A'-'A'07^ J NCA2 Qm CN I-A28 AX1j^nv ZyV-oIYj 7 FXZ Q CN I-A29 ACZaa AiAXaA Jl^N    \> NC '-^        AZ CN I-A30 I-A37 CN OMe I-A35 I-A36 CN I-A43 I-A56 II-A4 II-A5 III-A2 NH ?HO ^•■'"^OH III-A9 Nx, u CM CN NH III- 9ho. H ^-1-^0^ A10 N. , u II 1 OMe H 0 III- 9hok 0 A11 N. J u KK OMe III- ?hoK H 'N^^N\ O A12 N-___ / K^o Km OMe III- 9hoK Il 1\ H ®X O A13 ty II 1      / \^-0 KM OMe X    HO 9hc\>- O 11 ,OMe -V N 1 Me IV-A1 u sM h^7 H IV-A2 IV-A3 IV-A4 IV-A5 IV-A6 IV-A7 IV-A8 HO H HO N O X_,,OMe 1 „OMe ' N Me I ,OMe ' N Me HO HQ HQ 1 ,Me •' N Me X   HQ o 1 .Me ~| Me IV-A9 N. I ^0 11 A A r~N H IV- A10 N. / O^ x HQ 3°\V FXa RN H o J .Me J N | Me IV- A11 N x HO 3°kT flA r~^i H o JL .Me A N 1 Me A M IV- A12 cr N x HQ 3°kT RNZ H 0 1 .Me A N 1 Me 3^ x HQ jHO^ / IV- A13 Nx" a WoA 3M ^NZ H x   HQ jHO^ / IV- A14 zNx Q WoX 3U A' X   HQ jHOy / ' IV- A15 nk T vo VIa 3^ r^7 H x   HQ jViO^- IV- A16 <'X 3Vo V jj h^7 H x   HO IV- A17 3'3 N X-VV AN H 'd x   HQ jHO^ / IV- A18 Z z \\ / / W<3 H IV- A19 nJ u x HQ 3°\T ^^oA- 0 J .OMe ] Me Aoz IV- A20 nJ J .     HQ 3°\V aJ^oA. O J „OMe A N 1 Me M H )¾ N^V IV- A21 cr HQ HO. X ,n Jx ( TV '■^'o l 0 J .OMe A N Me Anz H x   HQ ^HO^J -1-'"^NMe2 IV- A22 vJ OLa 3^ H 20 25 V-A7 0) q f / ~~\ zs e 7 J \— /     <D OX / —< r r-o xj V-A8 x   HQ ?HO^X'x ^Me2 XXVSn HN-X^^    W X \^N     Y y OMe V-A9 \   HO Oun ' X°xZl NMe2 ^-Z Zn    Cy OMe V-A10 x   HQ J^H           N M e2 yO^Ul^N OMe V-A11 Z \    N OZ               ^== / ^ OMe V-A12 z x    N yO^^l^N OMe In certain embodiments, provided is the ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof, wherein the linking group is -Tr-L^L^L1-, wherein: Tr is absent, or Tr is any group; L3 is absent or is selected from a polypeptide fragment and a peptide fragment analog; L2 is absent or is selected from a linker fragment; L1 is a linking unit. In certain embodiments, provided is the ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof, wherein the linking group is -Tr-L3-L2-L1-, wherein: Tr is absent, or Tr is any group; L3 is absent or is selected from a polypeptide fragment; L2 is absent or is selected from a linker fragment; L1 is a linking unit. In certain embodiments, the linking group and the drug group are linked to form a structure selected from a structure represented by formula I-B: I-B wherein: X, X1, X2, ring B, ring C, R3, R4, R5, R6, R8a, R8b, R9a, R9b, R10, M, Tr, L3, L2, and L1 are defined as described in any one of the embodiments of the present disclosure; the wavy line indicates linking to the ligand by a nitrogen atom or a carbon atom on the L1 group. In certain embodiments, the linking group and the drug group are linked to form a structure selected from a structure represented by formula II-B': II-B' wherein: X, X1, X2, ring B, ring C, R3, R4, R5, R6, R7, m, n, W, U, Z, Y, Tr, L3, L2, and L1 are defined as described in any one of the embodiments of the present disclosure; the wavy line indicates linking to the ligand by a nitrogen atom or a carbon atom on the L1 group. In certain embodiments, the linking group and the drug group are linked to form a structure selected from a structure represented by formula II-B: HO HO \ ■1   \ / II-B wherein: X, X1, X2, ring B, ring C, R3, R4, R5, R6, R7, m, W, U, Z, Y, Tr, L3, L2, and L1 are defined as described in any one of the embodiments of the present disclosure; the wavy line indicates linking to the ligand by a nitrogen atom or a carbon atom on the L1 group. In certain embodiments, the linking group and the drug group are linked to form a structure selected from a structure represented by formula III-B': R8b ~R8a III-B' wherein: X, X1, X2, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R12, L, m, Tr, L3, L2, and L1 are defined as described in any one of the embodiments of the present disclosure; the wavy line indicates linking to the ligand by a nitrogen atom or a carbon atom on the L1 group. In certain embodiments, the linking group and the drug group are linked to form a structure selected from a structure represented by formula III-B: III-B wherein: X, X1, X2, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R12, m, Tr, L3, L2, and L1 are defined as described in any one of the embodiments of the present disclosure; the wavy line indicates linking to the ligand by a nitrogen atom or a carbon atom on the L1 group. In certain embodiments, the linking group and the drug group are linked to form a structure selected from a structure represented by formula IV-B: IV-B wherein: X, X1, X2, ring B, ring C, R3, R4, R7, R8a, R8b, R9a, R9b, R10, m, Q, Tr, L3, L2, and L1 are defined as described in any one of the embodiments of the present disclosure; the wavy line indicates linking to the ligand by a nitrogen atom or a carbon atom on the L1 group. In certain embodiments, the linking group and the drug group are linked to form a structure selected from a structure represented by formula V-B: V-B wherein: X, X1, X2, ring A, ring B, ring C, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, m, T, Tr, L3, L2, and L1 are defined as described in any one of the embodiments of the present disclosure; the wavy line indicates linking to the ligand by a nitrogen atom or a carbon atom on the L1 group. In certain embodiments, provided is a structure formed by linking the linking group and the drug group, wherein: L1 is a linking unit; L2 is -(C(RL21)2)r-, wherein r is a natural number from 0 to 50; any C(RL21)2 unit in L2 may be independently replaced with the following structural unit: -Cy-, -C(=O)-, -NRL22-, -O-, -S-, -S(=O)-, -S(=O)2-, -P(RL22)-, -P(=O)(RL22)-, -C(=S)-, -C(=NRL22)-, - N=N-, -CH=N-, -N=CH-, 1 = I, or ; -Cy- is selected from -phenylene-, -(5-8 membered)heteroarylene-, -(4-10 membered)heterocyclylene-, and -(C3-C10)cycloalkylene-, and -Cy- is unsubstituted, or each -Cy-is independently substituted with one or more RCx; RL21, RL22, and RCx are each independently selected from hydrogen, deuterium, halogen, nitro, -CN, -ORL2a, -SRL2a, -N(RL2a)2, -N+(RL2a)3, -C(=O)RL2a, -C(=O)ORL2a, -C(=O)-C(=O)RL2a, -C(=O)CH2C(=O)RL2a, -S(=O)RL2a, -S(=O)2RL2a, -C(=O)N(RL2a)2, -S(=O)2N(RL2a)2, -OC(=O)RL2a, -N(RL2a)S(=O)2RL2b, -N(RL2a)C(=O)RL2b, -(CH2)y-C(=O)-(N(Me)CH2C(=O))s-ORL2a, -(CH2)y-C(=O)-(N(Me)CH2C(=O))s-NHRL2a, -(CH2)y-C(=O)-(N(Me)CH2C(=O))s-N+(RL2a)3, -(CH2)y-NHC(=O)CH2(OCH2CH2)ORL2a, -(CH2)y-NH(C(=O)CH2(N(Me))s-RL2a, -(CH2)y-C(=O)NH-(CH2CH2O)s-RL2a,      -(CH2)y-NHC(=O)-(CH2CH2O)s-RL2a,      -(CH2CH2O)s-RL2a,      - (C(=O)CH2N(Me))s-RL2a, -C(=O)CH2(OCH2CH2)s-ORL2a, -C(=O)-(CH2CH2O)m-RL2a, -C(=O)-(CH2)y-C(=O)NH-(CH2CH2O)s-RL2a, -C(=O)-(CH2)y-NHC(=O)-(CH2CH2O)s-RL2a, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C3-C8)cycloalkyl, -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl, wherein the -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C3-C8)cycloalkyl, -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl are optionally substituted with one or more RL2a; s and y are each independently a natural number from 0 to 50; RL2a and RL2b are each independently selected from hydrogen, deuterium, halogen, nitro, -CN, -OH, -SH, -NH2, -N(Me)2, -C(=O)OH, -S(=O)2Me, -S(=O)2OH, -C(=O)NH2, -S(=O)2NH2, -(C1-C6)alkyl,        -(C2-C6)alkenyl,        -(C2-C6)alkynyl,        -(C3-C8)cycloalkyl,        -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl; L3 is absent or is selected from an amino acid residue, a short peptide consisting of 2-10 amino acid residues, -C(=O)-(C1-C6)alkylene-NH-, , and any combination of the aforementioned groups, wherein the amino acid residues are natural amino acid residues or nonnatural amino acid residues, and L3 is optionally modified by one or more protecting groups; in certain embodiments, the protecting groups are selected from a polyethylene glycol fragment and -OtBu, wherein the polyethylene glycol fragment is linked to L3 by the structural unit -NH-; Tr is absent or is selected from and any combination of the aforementioned groups; RTr, RTr1, and RTr2 are each independently selected from hydrogen, deuterium, halogen, nitro, -CN, -OH, -NH2, -SH, -OC(=O)NH2, -C(=O)OH, -C(=O)NH2, -S(=O)2OH, -S(=O)2NH2, -CH2C(=O)-(N(Me)CH2C(=O))z-ORTra, -CH2C(=O)-(N(Me)CH2C(=O))z-NHRTra, -(CH2CH2O)z-RTra, -C(=O)NH-(CH2CH2O)z-RTra, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C3-C8)cycloalkyl, -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl, wherein the -(C1-C6)alkyl,      -(C2-C6)alkenyl,      -(C2-C6)alkynyl,      -(C3-C8)cycloalkyl,      -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl are optionally substituted with one or more RTra; each RTra is independently hydrogen, deuterium, halogen, nitro, -CN, -OH, -NH2, -SH, -N(Me)2, -C(=O)OH, -C(=O)NH2, -S(=O)2OH, -S(=O)2NH2, -S(=O)2Me, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C3-C8)cycloalkyl, -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl; each z is independently a natural number from 0 to 50. In certain embodiments, provided is a structure formed by linking the linking group and the drug group, wherein: L1 is a linking unit; L2 is -(C(RL21)2)r-, wherein r is a natural number from 0 to 50; any C(RL21)2 unit in L2 may be independently replaced with the following structural unit: -Cy-, - C(=O)-, -NRL22-, -O-, -S-, -S(=O)-, -S(=O)2-, -P(RL22)-, -P(=O)(RL22)-, -C(=S)-, -C(=NRL22)-, - N=N-, -CH=N-, -N=CH-, or -Cy- is selected from -phenylene-, -(5-8 membered)heteroarylene-, -(4-10 membered)heterocyclylene-, and -(C3-C10)cycloalkylene-, and -Cy- is unsubstituted, or each -Cy-is independently substituted with one or more RCx; RL21, RL22, and RCx are each independently selected from hydrogen, deuterium, halogen, nitro, -CN, -ORL2a, -SRL2a, -N(RL2a)2, -N+(RL2a)3, -C(=O)RL2a, -C(=O)ORL2a, -C(=O)-C(=O)RL2a, -C(=O)CH2C(=O)RL2a, -S(=O)RL2a, -S(=O)2RL2a, -C(=O)N(RL2a)2, -S(=O)2N(RL2a)2, -OC(=O)RL2a, -N(RL2a)S(=O)2RL2b, -N(RL2a)C(=O)RL2b, -(CH2)y-C(=O)-(N(Me)CH2C(=O))s-ORL2a, -(CH2)y-C(=O)-(N(Me)CH2C(=O))s-NHRL2a, -(CH2)y-C(=O)-(N(Me)CH2C(=O))s-N+(RL2a)3, -(CH2)y-NHC(=O)CH2(OCH2CH2)ORL2a, -(CH2)y-NH(C(=O)CH2(N(Me))s-RL2a, -(CH2)y-C(=O)NH-(CH2CH2O)s-RL2a,      -(CH2)y-NHC(=O)-(CH2CH2O)s-RL2a,      -(CH2CH2O)s-RL2a,      - (C(=O)CH2N(Me))s-RL2a, -C(=O)CH2(OCH2CH2)s-ORL2a, -C(=O)-(CH2CH2O)m-RL2a, -C(=O)-(CH2)y-C(=O)NH-(CH2CH2O)s-RL2a, -C(=O)-(CH2)y-NHC(=O)-(CH2CH2O)s-RL2a, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C3-C8)cycloalkyl, -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl, wherein the -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C3-C8)cycloalkyl, -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl are optionally substituted with one or more RL2a; s and y are each independently a natural number from 0 to 50; RL2a and RL2b are each independently selected from hydrogen, deuterium, halogen, nitro, -CN, -OH, -SH, -NH2, -N(Me)2, -C(=O)OH, -S(=O)2Me, -S(=O)2OH, -C(=O)NH2, -S(=O)2NH2, -(C1-C6)alkyl,        -(C2-C6)alkenyl,        -(C2-C6)alkynyl,        -(C3-C8)cycloalkyl,        -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl; L3 is absent or is selected from an amino acid residue, a short peptide consisting of 2-10 amino acid residues, , and any combination of the aforementioned groups, wherein the amino acid residues are natural amino acid residues or non-natural amino acid residues, and L3 is optionally modified by one or more protecting groups; in certain embodiments, the protecting groups are selected from a polyethylene glycol fragment and -OtBu, wherein the polyethylene glycol fragment is linked to L3 by the structural unit -NH-; Tr is absent or is selected from , and any combination of the aforementioned groups; RTr, RTr1, and RTr2 are each independently selected from hydrogen, deuterium, halogen, nitro, -CN, -OH, -NH2, -SH, -OC(=O)NH2, -C(=O)OH, -C(=O)NH2, -S(=O)2OH, -S(=O)2NH2, -CH2C(=O)-(N(Me)CH2C(=O))z-ORTra, -CH2C(=O)-(N(Me)CH2C(=O))z-NHRTra, -(CH2CH2O)z-RTra, -C(=O)NH-(CH2CH2O)z-RTra, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C3-C8)cycloalkyl, -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl, wherein the -(C1-C6)alkyl,      -(C2-C6)alkenyl,      -(C2-C6)alkynyl,      -(C3-C8)cycloalkyl,      -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl are optionally substituted with one or more RTra; each RTra is independently hydrogen, deuterium, halogen, nitro, -CN, -OH, -NH2, -SH, -N(Me)2, -C(=O)OH, -C(=O)NH2, -S(=O)2OH, -S(=O)2NH2, -S(=O)2Me, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C3-C8)cycloalkyl, -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl; each z is independently a natural number from 0 to 50. In certain embodiments, L1 is selected from carbonyl, -(C1-C8)alkylene-C(=O)-, -(4-8 membered)heterocyclylene-, -(5-10 membered)heteroarylene-, and -(C1-C8)alkylene-(5-10 membered)heteroarylene-, wherein the      -(C1-C8)alkylene-C(=O)-,       -(4-8 membered)heterocyclylene-, -(5-10 membered)heteroarylene-, and -(C1-C8)alkylene-(5-10 membered)heteroarylene- are optionally substituted with 1, 2, or 3 oxo, -(C1-C4)alkylene-, and -(C1-C4)alkyl groups. In certain embodiments, L1 is selected from carbonyl, -(C1-C4)alkylene-C(=O)-, -(5-6 membered)heterocyclylene-, -(5-6 membered)heteroarylene-, and -(C1-C4)alkylene-(5-6 membered)heteroarylene-, wherein the      -(C1-C4)alkylene-C(=O)-,       -(5-6 membered)heterocyclylene-, -(5-6 membered)heteroarylene-, and -(C1-C4)alkylene-(5-6 membered)heteroarylene- are optionally substituted with 1, 2, or 3 oxo, -(C1-C4)alkylene-, and - (C1-C4)alkyl groups. In certain embodiments, L1 is selected from In certain embodiments, L1 is selected from 0 In certain embodiments, L1 is selected from and wherein the * end is attached to L2. o In certain embodiments, L1 is selected from "< ° , wherein the * end is attached to L2. In certain embodiments, L2 is -(C(RL21)2)r-, wherein r is a natural number from 0 to 10 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, or 9); any C(RL21)2 unit in L2 may be independently replaced with the following structural unit: -Cy-, -C(=O)-, -NRL22-, -O-, -S-, or -S(=O)-; -Cy- is selected from -phenylene-, -4-6 membered heterocyclylene-, and -(C3-C6)cycloalkylene-, and -Cy- is unsubstituted, or each -Cy- is independently substituted with 1, 2, 3, 4, 6, or 7 RCx; RL21, RL22, and RCx are each independently selected from hydrogen, deuterium, halogen, nitro, -CN, -ORL2a, -SRL2a, -N(RL2a)2, -C(=O)RL2a, -C(=O)ORL2a, -C(=O)-C(=O)RL2a, -C(=O)CH2C(=O)RL2a, -S(=O)RL2a, -S(=O)2RL2a, -C(=O)N(RL2a)2, -S(=O)2N(RL2a)2, -(CH2)2-C(=O)NH-(CH2CH2O)t-RL2a, -(C1-C6)alkyl, and -(C2-C6)alkenyl, wherein the -(C1-C6)alkyl and -(C2-C6)alkenyl are optionally substituted with 1, 2, 3, 4, 5, 6, or 7 RL2a; t is a natural number from 0 to 30; RL2a is selected from hydrogen, deuterium, fluorine, chlorine, bromine, iodine, nitro, -CN, -OH, -SH, -NH2, -N(Me)2, -C(=O)OH, -S(=O)2Me, -S(=O)2OH, -C(=O)2OH, -C(=O)NH2, -S(=O)2NH2, methyl, ethyl, and vinyl. In certain embodiments, L2 is -(C(RL21)2)r-, wherein r is a natural number from 0 to 10 (e.g., 1, 2, 3, 4, 5, 6, 7, or 8); any C(RL21)2 unit in L2 may be independently replaced with the following structural unit: -Cy-, -C(=O)-, -NRL22-, -O-, -S-, or -S(=O)-; -Cy- is selected from -phenylene-, -4-6 membered heterocyclylene-, and -(C3-C6)cycloalkylene-, and -Cy- is unsubstituted, or each -Cy- is independently substituted with 1, 2, 3, 4, 6, or 7 RCx; RL21, RL22, and RCx are each independently selected from hydrogen, deuterium, halogen, nitro, -CN, -ORL2a, -SRL2a, -N(RL2a)2, -C(=O)RL2a, -C(=O)ORL2a, -C(=O)-C(=O)RL2a, -C(=O)CH2C(=O)RL2a, -S(=O)RL2a, -S(=O)2RL2a, -C(=O)N(RL2a)2, -S(=O)2N(RL2a)2, -(CH2)2-C(=O)NH-(CH2CH2O)t-RL2a, -(C1-C6)alkyl, and -(C2-C6)alkenyl, wherein the -(C1-C6)alkyl and -(C2-C6)alkenyl are optionally substituted with 1, 2, 3, 4, 5, 6, or 7 RL2a; t is a natural number from 0 to 30; RL2a is selected from hydrogen, deuterium, fluorine, chlorine, bromine, iodine, nitro, -CN, -OH, - SH, -NH2, -N(Me)2, -C(=O)OH, -S(=O)2Me, -S(=O)2OH, -C(=O)2OH, -C(=O)NH2, -S(=O)2NH2, methyl, ethyl, and vinyl. In certain embodiments, L2 is -(C(RL21)2)r-, wherein r is 2, 3, 4, 5, 6, 7, 8, or 9, and any C(RL21)2 unit in L2 may be independently replaced with the following structural unit: -Cy-, -C(=O)-, -NRL22-, -O-, -S-, or -S(=O)-; -Cy- is selected from cyclopropylene, cyclobutylene, cyclopentylene, azetidinylene, pyrrolidinylene, piperazinylene, or piperidinylene, and -Cy- is unsubstituted, or each -Cy- is independently substituted with 1, 2, 3, 4, or 5 RCx; for example, -Cy- is I— N N—I   kN \— /   , or ' RL21, RL22, and RCx are each independently selected from hydrogen, deuterium, fluorine, chlorine, bromine, iodine, nitro, -CN, -OH, -SH, -NH2, -C(=O)OH, -C(=O)NH, -(CH2)2-C(=O)NH-(CH2CH2O)11-CH3, methyl, ethyl, propyl, deuterated methyl, deuterated ethyl, halomethyl, haloethyl, methyl-OH, ethyl-OH, propyl-OH, vinyl-OH, vinyl, deuterated vinyl, and halovinyl. In certain embodiments, L2 is -(C(RL21)2)r-, wherein r is 2, 3, 4, 5, 6, 7, or 8; any C(RL21)2 unit in L2 may be independently replaced with the following structural unit: -Cy-, -C(=O)-, -NRL22-, -O-, -S-, or -S(=O)-; -Cy- is selected from cyclopropylene, cyclobutylene, cyclopentylene, azetidinylene, pyrrolidinylene, piperazinylene, or piperidinylene, and -Cy- is unsubstituted, or each -Cy- is independently substituted with 1, 2, 3, 4, or 5 RCx; for example, -Cy- is RL21, RL22, and RCx are each independently selected from hydrogen, deuterium, fluorine, chlorine, bromine, iodine, nitro, -CN, -OH, -SH, -NH2, -C(=O)OH, -C(=O)NH, -(CH2)2-C(=O)NH-(CH2CH2O)11-CH3, methyl, ethyl, propyl, deuterated methyl, deuterated ethyl, halomethyl, haloethyl, methyl-OH, ethyl-OH, propyl-OH, vinyl-OH, vinyl, deuterated vinyl, and halovinyl. In certain embodiments, L2 is selected from In certain embodiments, L2 is selected from 10 In certain embodiments, L2 is selected from o and o and              , wherein the * end is attached to L3. In certain embodiments, O L2 is selected from wherein the * end is attached to L3. In certain embodiments, L2 is selected from and and , wherein the * end is attached to L3. In certain embodiments, L2 is selected from end is attached to L3. In certain embodiments, -L1-L2- is * and wherein the * selected from In certain embodiments, -L1-L2- is selected 0 from , H N , and In certain embodiments, -L1-L2- is selected , and from 5 wherein the * end is attached to L3. In certain embodiments, -L1-L2- is selected from O and wherein the * end is attached to L3. 10 In certain embodiments, -L1-L2- is selected and In certain embodiments, the amino acid residue is selected from Val, D-Val, Phe, Lys, Leu, Ile, Gly, Ala, D-Ala, Cit, Asp, Asn, Glu, Gln, Arg, and Ser; the short peptide consisting of 2-10 amino acid residues is selected from -Arg-Val-, -Arg-Leu-, -Val-Cit-, -Val-Ala-, -Val-Lys-, -Val-Lys(AC)-, -Phe-Lys-, -Phe-Lys(AC)-, -Leu-Lys-, -Leu-Lys(AC)-, -Ala-Ala-, -Ala-Lys-, -(D-Ala)-Ala-, -Gly-Glu-, -Gly-Asp-, -Gly-Asn-, -Val-Glu-, -Val-Asp-, -Asn-Asn-, -Asp-Asp-, -Asp-Glu-, -Ser-Val-, -Ser-Ala-, -Ser-Gly-, -Ser-Glu-, -Ser-Gln-, -Ser-Asp-, -Gly-Gln-, -Asn-Gly-, -Asn-Ala-, -Ala-Ala-Glu-, -Gly-Gly-Glu-, -Gly-Gly-Asp-, -Gly-Gly-Asn-, -Gly-Ala-Ala-, -Gly-Val-Ala-, -Gly-Val-Cit-, -Glu-Val-Cit-, -Ala-Ala-Ala-, -Ala-(D-Ala)-Ala-, -Ala-Ala-Asn-, -Ala-(D-Ala)-Asn-, -Ala-Ala-Asp-, -Val-Lys-Gly-, -(D-Val)-Leu-Lys-, -Gly-Gly-Arg-, -Gly-Gly-Gly-, -Lys-Ala-Asn-, -Gly-Phe-Gly-, -Gly-Gly-Phe-, -Asn-Pro-Val-, -Ala-Lys-Gly-, -Gly-Lys-Gly-, -Gly-Gly-Gly-Gly- (SEQ ID NO: 61), -Gly-Gly-Phe-Gly- (SEQ ID NO: 62), -Gly-Gly-Glu-Gly- (SEQ ID NO: 63), -Lys-Ala-Ala-Asn- (SEQ ID NO: 64), -Lys-Ala-Ala-Asp- (SEQ ID NO: 65), -Ala-Ala-Pro-Val- (SEQ ID NO: 66), and -Ala-Ala-Pro-Nva- (SEQ ID NO: 67); the polyethylene glycol fragment is selected from -(CH2CH2O)t-RL3, wherein RL3 is -(C1-C6)alkyl, and t is an integer from 6 to 30. In certain embodiments, the amino acid residue is selected from Val, D-Val, Phe, Lys, Leu, Ile, Gly, Ala, D-Ala, Cit, Asp, Asn, Glu, Gln, Arg, and Ser; the short peptide consisting of 2-10 amino acid residues is selected from -Arg-Val-, -Arg-Leu-, -Val-Cit-, -Val-Ala-, -Val-Lys-, -Val-Lys(AC)-, -Phe-Lys-, -Phe-Lys(AC)-, -Leu-Lys-, -Leu-Lys(AC)-, -Ala-Ala-, -Ala-Lys-, -(D-Ala)-Ala-, -Gly-Glu-, -Gly-Asp-, -Gly-Asn-, -Val-Glu-, -Val-Asp-, -Asn-Asn-, -Asp-Asp-, -Asp-Glu-, -Ser-Ala-, -Ser-Gly-, -Ser-Glu-, -Ser-Asp-, -Gly-Gln-, -Ala-Ala-Glu-, -Gly-Gly-Glu-, -Gly-Gly-Asp-, -Gly-Gly-Asn-, -Gly-Ala-Ala-, -Gly-Val-Ala-, -Gly-Val-Cit-, -Glu-Val-Cit-, -Ala-Ala-Ala-, -Ala-(D-Ala)-Ala-, -Ala-Ala-Asn-, -Ala-(D-Ala)-Asn-, -Ala-Ala-Asp-, -Val-Lys-Gly-, -(D-Val)-Leu-Lys-, -Gly-Gly-Arg-, -Gly-Gly-Gly-, -Lys-Ala-Asn-, -Gly-Phe-Gly-, -Gly-Gly-Phe-, -Asn-Pro-Val-, -Ala-Lys-Gly-, -Gly-Lys-Gly-, -Gly-Gly-Gly-Gly-, -Gly-Gly-Phe-Gly-, -Gly-Gly-Glu-Gly-, -Lys-Ala-Ala-Asn-, -Lys-Ala-Ala-Asp-, -Ala-Ala-Pro-Val-, and -Ala-Ala-Pro-Nva-; the polyethylene glycol fragment is selected from -(CH2CH2O)t-RL3, wherein RL3 is -(C1-C6)alkyl, and t is an integer from 6 to 30. In certain embodiments, L3 is selected from Val, D-Val, Phe, Lys, Leu, Ile, Gly, Ala, D-Ala, Cit, Asp, Asn, Glu, Gln, Arg, Ser, -Arg-Val-, -Arg-Leu-, -Val-Cit-, -Val-Ala-, -Val-Lys-, -Val-Lys(AC)-, -Phe-Lys-, -Phe-Lys(AC)-, -Leu-Lys-, -Leu-Lys(AC)-, -Ala-Ala-, -Ala-Lys-, -(D-Ala)-Ala-, -Gly-Glu-, -Gly-Asp-, -Gly-Asn-, -Val-Glu-, -Val-Asp-, -Asn-Asn-, -Asp-Asp-, -Asp-Glu-, -Ser-Val-, -Ser-Ala-, -Ser-Gly-, -Ser-Glu-, -Ser-Gln-, -Ser-Asp-, -Gly-Gln-, -Asn-Gly-, -Asn-Ala-, -Ala-Ala-Glu-, -Gly-Gly-Glu-, -Gly-Gly-Asp-, -Gly-Gly-Asn-, -Gly-Ala-Ala-, -Gly-Val-Ala-, -Gly-Val-Cit-, -Glu-Val-Cit-, -Ala-Ala-Ala-, -Ala-(D-Ala)-Ala-, -Ala-Ala-Asn-, -Ala-(D-Ala)-Asn-, -Ala-Ala-Asp-, -Val-Lys-Gly-, -(D-Val)-Leu-Lys-, -Gly-Gly-Arg-, -Gly-Gly-Gly-, -Lys-Ala-Asn-, -Gly- Phe-Gly-, -Gly-Gly-Phe-, -Asn-Pro-Val-, -Ala-Lys-Gly-, -Gly-Lys-Gly-, -Gly-Gly-Gly-Gly-, -Gly-Gly-Phe-Gly-, -Gly-Gly-Glu-Gly-, -Lys-Ala-Ala-Asn-, -Lys-Ala-Ala-Asp-, -Ala-Ala-Pro- Val-, -Ala-Ala-Pro-Nva-, , -C(=O)-(C1-C4)alkylene-NH-, and any combination of the aforementioned groups, wherein Asp and Glu are each independently and optionally modified by -(CH2CH2O)t-RL3, wherein -(CH2CH2O)t-RL3 is linked to Asp or Glu by the structural unit -NH-, RL3 is -(C1-C4)alkyl, and t is an integer from 6 to 30 (e.g., 8, 9, 10, 11, 12, 13, 14, 15, 20, 21, 22, 23, 24, or 25). In certain embodiments, L3 is selected from Val, D-Val, Phe, Lys, Leu, Ile, Gly, Ala, D-Ala, Cit, Asp, Asn, Glu, Gln, Arg, -Arg-Val-, -Arg-Leu-, -Val-Cit-, -Val-Ala-, -Val-Lys-, -Val-Lys(AC)-, -Phe-Lys-, -Phe-Lys(AC)-, -Leu-Lys-, -Leu-Lys(AC)-, -Ala-Ala-, -Ala-Lys-, -D-Ala-Ala-, -Gly-Glu-, -Gly-Asp-, -Gly-Asn-, -Val-Glu-, -Val-Asp-, -Asn-Asn-, -Asp-Asp-, -Asp-Glu-, -Ser-Ala-, - Ser-Gly-, -Ser-Glu-, -Ser-Asp-, -Gly-Gln-, -Ala-Ala-Glu-, -Gly-Gly-Glu-, -Gly-Gly-Asp-, -Gly-Gly-Asn-, -Gly-Ala-Ala-, -Gly-Val-Ala-, -Gly-Val-Cit-, -Glu-Val-Cit-, -Ala-Ala-Ala-, -Ala-(D-Ala)-Ala-, -Ala-Ala-Asn-, -Ala-(D-Ala)-Asn-, -Ala-Ala-Asp-, -Val-Lys-Gly-, -D-Val-Leu-Lys-, - Gly-Gly-Arg-, -Gly-Gly-Gly-, -Lys-Ala-Asn-, -Gly-Phe-Gly-, -Gly-Gly-Phe-, -Asn-Pro-Val-, -Ala-Lys-Gly-, -Gly-Lys-Gly-, -Gly-Gly-Gly-Gly-, -Gly-Gly-Phe-Gly-, -Gly-Gly-Glu-Gly-, -Lys- -Lys-Ala-Ala-Asp-, -Ala-Ala-Pro-Val-, -Ala-Ala-Pro-Nva-, Ala-Ala-Asn-, and any combination of the aforementioned groups, wherein Asp and Glu are each independently and optionally modified by -(CH2CH2O)t-RL3, wherein (CH2CH2O)t-RL3 is linked to Asp or Glu by the structural unit -NH-, RL3 is -(C1-C4)alkyl, and t is an integer from 6 to 30 (e.g., 8, 9, 10, 11, 12, 13, 14, 15, 20, 21, 22, 23, 24, or 25). In certain embodiments, L3 is selected from -Val-Cit-, -Arg-Val-, -Ala-Ala-, -Val-Ala-, -Gly-Glu-, -Ser-Val-, -Ser-Ala-, -Ser-Gly-, -Ser-Glu-, -Ser-Gln-, -Ser-Asp-, -Gly-Gln-, -Gly-Asp-, -Gly-Asn-, -Asp-Asp-, -Asp-Glu-, -Asn-Gly-, -Asn-Ala-, -Ala-Ala-Ala-, -Ala-Ala-Glu-, -Gly-Ala-Ala-, -Gly- Gly-Glu-, -Gly-Gly-Phe-Gly-, and -C(=O)-(C1-C4)alkylene-NH-, wherein Asp and Glu are each independently and optionally modified by -(CH2CH2O)t-RL3, wherein (CH2CH2O)t-RL3 is linked to Asp or Glu by the structural unit -NH-, RL3 is -(C1-C4)alkyl, and t is an integer from 6 to 30 (e.g., 8, 9, 10, 11, 12, 13, 14, 15, 20, 21, 22, 23, 24, or 25). In certain embodiments, L3 is selected from -Val-Cit-, -Arg-Val-, -Ala-Ala-, -Val-Ala-, -Gly-Glu-, -Ser-Ala-, -Ser-Gly-, -Ser-Glu-, -Ser-Asp-, -Gly-Gln-, -Gly-Asp-, -Gly-Asn-, -Asp-Asp-, -Asp-Glu-, -Ala-Ala-Ala-, -Ala-Ala-Glu-, -Gly-Ala-Ala-, -Gly-Gly-Glu-, -Gly-Gly-Phe-Gly-, or ho"% , wherein Asp and Glu are each independently and optionally modified by -(CH2CH2O)t-RL3, wherein (CH2CH2O)t-RL3 is linked to Asp or Glu by the structural unit -NH-, RL3 is -(C1-C4)alkyl, and t is an integer from 6 to 30 (e.g., 8, 9, 10, 11, 12, 13, 14, 15, 20, 21, 22, 23, 24, or 25). In certain embodiments, L3 is selected from -Val-Cit-, -Arg-Val-, -Ala-Ala-, -Val-Ala-, -Gly-Glu-, -Ser-Val-, -Ser-Ala-, -Ser-Gly-, -Ser-Glu-, -Ser-Gln-, -Ser-Asp-, -Gly-Gln-, -Asn-Gly-, -Asn-Ala-, -Ala-Ala-Glu-, -Gly-Ala-Ala-, -Gly-Gly-Glu-, -Gly-Gly-Phe-Gly-, -Ala-Ala-Glu(NH-(CH2CH2O)t-RL3)-, and -C(=O)-CH2CH2-NH-, wherein RL3 is -(C1-C4)alkyl, and t is an integer from 6 to 30; an example is -Ala-Ala-Glu(NH-(CH2CH2O)11-CH3)- or -Ala-Ala-Glu(NH-(CH2CH2O)24-CH3)-. In certain embodiments, L3 is selected from -Val-Cit-, -Arg-Val-, -Ala-Ala-, -Gly-Glu-, -Ser-Ala-, -Ser-Gly-, -Ser-Glu-, -Ser-Asp-, -Gly-Gln-, -Ala-Ala-Glu-, -Gly-Ala-Ala-, -Gly-Gly-Glu-, -Gly-Gly-Phe-Gly-, and -Ala-Ala-Glu(NH-(CH2CH2O)t-RL3)-, wherein RL3 is -(C1-C4)alkyl, and t is an integer from 6 to 30; an example is -Ala-Ala-Glu(NH-(CH2CH2O)11-CH3)- or -Ala-Ala-Glu(NH-(CH2CH2O)24-CH3)-. In certain embodiments, L3 is selected from -Val-Cit-*, *-Ala-Ala-, -Val-Ala-*, *-Gly-Glu-, *-Ser-Val-, *-Ser-Ala-, *-Ser-Gly-, *-Ser-Glu-, *-Ser-Gln-, *-Ser-Asp-, -Gly-Gln-*, *-Gly-Gln-, *-Asn-Gly-, *-Asn-Ala-, *-Gly-Ala-Ala-, *-Gly-Gly-Glu-, -Gly-Gly-Phe-Gly-*, *-Ala-Ala-Glu(NH-O (CH2CH2O)ii-CH3)-, and           H , wherein the * end is attached to Tr. In certain embodiments, L3 is selected from -Val-Cit-*, *-Ala-Ala-, *-Gly-Glu-, *-Ser-Ala-, *-Ser- Gly-, *-Ser-Glu-, *-Ser-Asp-, -Gly-Gln-*, *-Gly-Ala-Ala-, *-Gly-Gly-Glu-, -Gly-Gly-Phe-Gly-*, and *-Ala-Ala-Glu(NH-(CH2CH2O)11-CH3)-, wherein the * end is attached to Tr. In certain embodiments, L3 is selected from -Val-Cit-*, *-Ala-Ala-, -Val-Ala-*, *-Gly-Glu-, *-Ser-Val-, *-Ser-Ala-, *-Ser-Gly-, *-Ser-Glu-, *-Ser-Gln-, *-Ser-Asp-, -Gly-Gln-*, *-Gly-Gln-, *-Asn-Gly-, *-Asn-Ala-, *-Gly-Ala-Ala-, *-Gly-Gly-Glu-, -Gly-Gly-Phe-Gly-*, *Ala-Ala-C(=O)-0 CH[CH2CH2-C(=O)-NH-(CH2CH2O)11-CH3]-NH-, and          H , wherein the * end is attached to Tr. In certain embodiments, L3 is selected from -Val-Cit-*, *-Ala-Ala-, *-Gly-Glu-, *-Ser-Ala-, *-Ser-Gly-, *-Ser-Glu-, *-Ser-Asp-, -Gly-Gln-*, *-Gly-Ala-Ala-, *-Gly-Gly-Glu-, -Gly-Gly-Phe-Gly-*, and *-Ala-Ala-C(=O)-CH[CH2CH2-C(=O)-NH-(CH2CH2O)11-CH3]-NH-, wherein the * end is attached to Tr. In certain embodiments, L3 is selected from -Glu-Ser-, -Ala-Ser-, -Gly-Ser-, and -Asp-Ser-. In certain embodiments, L3 is selected from *-Ala-Ala-, *-Gly-Glu-, and *-Gly-Gly-Glu-, wherein the * end is attached to Tr. 0 In certain embodiments, L3 is selected from *-Ala-Ala- and           H , wherein the * end is attached to Tr. In certain embodiments, L3 is selected from O wherein the * end is attached to Tr. In certain embodiments, Tr is absent or is selected from and RTr, RTr1, and RTr2 are each independently selected from hydrogen, deuterium, halogen, nitro, -CN, -OH, -NH2, -SH, -OC(=O)NH2, -C(=O)OH, -C(=O)NH2, -S(=O)2OH, -S(=O)2NH2, -(CH2CH2O)z-RTra, -C(=O)NH-(CH2CH2O)z-RTra, gluconolactone, glucuronic acid, -(C1-C4)alkyl, and -(C2-C4)alkenyl, wherein the -(C1-C4)alkyl and -(C2-C4)alkenyl are optionally substituted with 1, 2, 3, 4, or 5 RTra; each RTra is independently hydrogen, deuterium, halogen, nitro, -CN, -OH, -NH2, -SH, -N(Me)2, -C(=O)OH, -C(=O)NH2, -S(=O)2OH, -S(=O)2NH2, -S(=O)2Me, -(C1-C4)alkyl, or -(C2-C4)alkenyl; each z is independently an integer from 6 to 30. o                               RTr1 / Tr2 AJL AnX4 hN 7 In certain embodiments, Tr is absent or is selected from > , h RTr , and ! H RTr, RTr1, and RTr2 are each independently selected from hydrogen, deuterium, halogen, nitro, -CN, -OH, -NH2, -SH, -OC(=O)NH2, -C(=O)OH, -C(=O)NH2, -S(=O)2OH, -S(=O)2NH2, -(CH2CH2O)z-RTra, -C(=O)NH-(CH2CH2O)z-RTra, -(C1-C4)alkyl, and -(C2-C4)alkenyl, wherein the -(C1-C4)alkyl and -(C2-C4)alkenyl are optionally substituted with 1, 2, 3, 4, or 5 RTra; each RTra is independently hydrogen, deuterium, halogen, nitro, -CN, -OH, -NH2, -SH, -N(Me)2, -C(=O)OH, -C(=O)NH2, -S(=O)2OH, -S(=O)2NH2, -S(=O)2Me, -(C1-C4)alkyl, or -(C2-C4)alkenyl; each z is independently an integer from 6 to 30. In certain embodiments, RTr, RTr1, and RTr2 are each independently selected from hydrogen, deuterium, fluorine, chlorine, bromine, iodine, nitro, -CN, -OH, -NH2, -SH, -OC(=O)NH2, -C(=O)OH, -C(=O)NH2, -S(=O)2OH, -S(=O)2NH2, -(CH2CH2O)z-RTra, -C(=O)NH-(CH2CH2O)z-RTra, gluconolactone, glucuronic acid, methyl, ethyl, -ethylene-OH, and -CH2-COOH; each RTra is independently hydrogen, deuterium, fluorine, chlorine, bromine, iodine, -CN, -OH, -NH2, -SH, -N(Me)2, -C(=O)OH, -C(=O)NH2, methyl, or ethyl; each z is independently an integer from 6 to 30 (e.g., 8, 9, 10, 11, 12, 13, 14, 15, 20, 21, 22, 23, 24, or 25). In certain embodiments, RTr, RTr1, and RTr2 are each independently selected from hydrogen, deuterium, fluorine, chlorine, bromine, iodine, nitro, -CN, -OH, -NH2, -SH, -OC(=O)NH2, -C(=O)OH, -C(=O)NH2, -S(=O)2OH, -S(=O)2NH2, -(CH2CH2O)z-RTra, -C(=O)NH-(CH2CH2O)z-RTra, methyl, ethyl, -ethylene-OH, and -CH2-COOH; each RTra is independently hydrogen, deuterium, fluorine, chlorine, bromine, iodine, -CN, -OH, -NH2, -SH, -N(Me)2, -C(=O)OH, -C(=O)NH2, methyl, or ethyl; each z is independently an integer from 6 to 30 (e.g., 8, 9, 10, 11, 12, 13, 14, 15, 20, 21, 22, 23, 24, or 25). OH HOk A .COOH In certain embodiments, RTr is selected from hydrogen, -CH2-COOH, and In certain embodiments, RTr is selected from hydrogen and -CH2-COOH In certain embodiments, Tr is absent or is selected from 0 In certain embodiments, Tr is absent or is selected from , and In certain embodiments, Tr is absent or is selected from wherein the * end is attached to L3. In certain embodiments, Tr is absent or is selected from * * wherein the * end is attached to L3. In certain embodiments, Tr is absent or is OH wherein the * end 10 is attached to L3. PN In certain embodiments, Tr is absent or is * H wherein the * end is attached to L3. In certain embodiments, -L3-L2-L1- is selected from H2N h2n In certain embodiments, -L3-L2-L1- is selected from and In certain embodiments, -L3-L2-L1- is selected from and In certain embodiments, -L3-L2-L1- is selected from and 10 In certain embodiments, -Tr-L3-L2-L1-        is selected from and In certain embodiments, -Tr-L3-L2-L1- is In certain embodiments, -Tr-L3-L2-L1- is OH 5 In certain embodiments, -L1-L2-L3- 0 H           . J? . AVAYA 0 A °           , I                  / An HO^O                    ,   o 1 0 - 0 H            A 1 0 H : A / N-A     V\ AAAn / 1   A   AA \       l! H I 0         0             o / / o                      ,    A) Z% H        f AVaYh a o H 1 0      <A       0 , A H   ^A . A A A / N-aa-^AAA / A<n A A      i / *   z ° Y 0        Y oah , n                $ L JI                                 o.                     \\ 9 h ? 9 h    9      YAj   I—A Yaa          rV 5            o H      o H               o , and In certain embodiments, -L1-L2-L3- is selected from H Y^a0 E O     A O A / k JA / N / A' JA / °\^ / A / J Ar n A A n a o T II H 1 H H     Vn^^n o                 , =    ° H                       fl° AVaYM I H H 1 o         A-7         X 0          u        o             x , HO^O T          ov-\ o          Q          'A”)—j A^         A Y H          o H       0 , Y              H 9 I H 9 An^^^^AT YA|AyN^A / M,       o a H <5 = 0 \ O^NH , Y H         . A A^n^^-A-nAA N            f|                    | / * H 0    cA , -^0¾ H                fl -nAny^^xA A °    o^7 OH , O^NHz H ? I X - / \ / -\ / -\ A / A A n         Ar '-' N ; s a 7 A       0    H 0 o . H E 0 H       9       0 C a^ / A^n. a / A / \ A i At nA A n   nAJ o H     o H     A~A o          , °A Ya » b A......... O^OH , 0 aYa^aY II H i 0            0 0 , . 7'7........'...... HO 0                        , and In certain embodiments, -L1-L2-L3- is selected from . HO^O O H ; Hu    " H and 0          0 0 777 3-7' In certain embodiments, -L1-L2-L3- is selected from O                           0 0 and In certain embodiments, the linking group and the drug group are linked to form a structure selected from a structure represented by formula I-B-1, II-B-1', II-B-1, III-B-1', III-B-1, IV-B-1, or V-B-1: 10 l3 Al LL2 III-B-1 IV-B-1 5                                   II-B-1'                                  III-B-1' wherein X, X1, X2, ring A, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, R12, m, n, M, W, U, Z, Y, L, Q, T, Tr, L1, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. 10 In certain embodiments, the linking group and the drug group are linked to form a structure selected from a structure represented by formula I-B-2, II-B-2', II-B-2, III-B-2', III-B-2, IV-B-2, or V-B-2: 15 I-B-2 II-B-2 10 2.xl X2 ' R3 y R4 II-B-2'                              III-B-2' wherein X, X1, X2, ring A, R3, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, R12, m, n, M, W, U, Z, Y, L, Q, T, Tr, L1, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the linking group and the drug group are linked to form a structure selected from a structure represented by formula I-B-3, III-B-3', III-B-3, IV-B-3, or V-B-3: I-B-3                                     III-B-3 IV-B-3 III-B-3' wherein X, X1, X2, ring A, R3, R4, R5, R6, R7, R8b, R9b, R12, m, M, L, Q, T, Tr, L1, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the linking group and the drug group are linked to form a structure selected from a structure represented by formula I-B-4, II-B-4', II-B-4, III-B-4', III-B-4, IV-B-4, 10 or V-B-4: I-B-4                                     II-B-4 III-B-4                               IV-B-4 V-B-4 II-B-4'                                   III-B-4' 5 wherein X, R1, ring A, R3, R4, R5, R6, R7, R8b, R12, m, n, M, W, U, Z, Y, L, Q, T, Tr, L1, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the linking group and the drug group are linked to form a structure selected from a structure represented by formula I-B-5, II-B-5, III-B-5, IV-B-5, or V-B-5: 10 I 3 , Ll LL2'L V-B-5 wherein X, R1, ring A, R3, R5, R6, R7, R8b, R9a, R9b, R12, n, M, W, U, Z, Y, L, Q, T, Tr, L1, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. 5 In certain embodiments, the linking group and the drug group are linked to form a structure selected from structures represented by formulas I-B-6 and I-B-7: I-B-6 I-B-7 10 wherein R1, R31, R5, R6, R8b, R9a, R9b, M, Tr, L1, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the linking group and the drug group are linked to form a structure selected from the structures shown in Table B below: 15                                             Table B No. Structure I-B1 k =o :t =O A J xo^ I-B8 I-B9 . HO ?HO. > I-B13 ,N. >-=ys.......-....."P' HO^O CN I-B14 \ O a )       >=A ) < ( o           \ o (         >° U  I o )       ° \ ° °\ o ( y—\ zi $ o        iz O         ZI '    .....A ® \___ od ® V / / O M 4^0 I-B15 •. . •. : o ( . e ■ • „ / O        IZ d O         ZI '    .....A IZ Za ° vy \3 I-B16 NC ° cb «       h h I h ? rVdXXl vo>^ 11 H We / vXX''1 f \  1                - H       - u                      < Ac^x X VA      OA H 0 o H        MeO     \ 1                                     0 OH °\ O' NH I-B17 NC o                            0      1 J v-X h 9 i H ? inA XI v°-^\ Ui v-yN^^A i ^naj 0 a rrurv 0    0 > H 0 = H       Meo' y"Xr 1                                       0 OH 0 O' NH |o''0'' o'0 . / 0 / I-B18 Gi®7 °4Vo°s z Xs^ / )__ / dx<“ \ o ZI “ °=< o & ZI A.....    , xz         o ZI        o X.o. 1 d       °\ J  (f X p z=<       < p V     o < 1 I-B19 z °'P? Ox oXW)°5 z \=y )_ / / ^X o A^0 W^x \       <D ZI 2 °=< o $ ZI A     , xz         o ZI        o Xo. 1 1 v XI °v Po o o 2 j u z-X    o \ / \ /           ( ° -U      o / 0 I-B20 NC 0                          0      I J H 9 I H 9 rV^O^NAA 0     0    H 0    H         Me Y'AjhT [                                   0 OH 0 O' NH O / q / ^O / I-B21 H h o (        >° Y  P o >       o ( o o o=\ <° AH.Y ) 1 >=> O        IZ °^< O         ZI '      .....Vo IZ o Y° 2 IZ <D         \____ zs A o=f 0 V / ■A / O vJ AO Z\^J I-B22 HD 0 iho.MV"6     H       I 5 N^A^oVjf J O H   0    O-^ A° CN I-B23 HA 0 >Ovk.AN^Me / 0¾ H         9 N / A^     J    H   o v° CN I-B24 HA 0 >AA'KN^0MHe      H         ? /              o H J 0     0^7 v° (A       r A;        cron CN I-B25 HA 0 >xXAN'0MHe      H        I t nAA-o    J 6      0     0-^7 U            OH CN I-B26 ho 0                    H       9 H                ,9 MOyoA ° ‘ ° u n- j CN I-B27 NC < 0               0   O O  H 9 i H 9 rVo^NAl Vvvll r^OO 0 Aw " 0 H ° = H 1                                            OH 0\ O'NH 0 o'' 0''"oA^ I-B28 Q V K M A J o >        ° \ ° °\ °^ o ( y—. zi $ o^o O         IZ O          ZI '      .....Vo IZ o ^==o IZ Za ^cvch oX° ° V / Xo I-B29 NC zO                              0 fA fi J        _ H Me           /  N'" 0   ()   "(>"     MeO y\% / 1                                    0 OH 0\ O' NH OxO^Q^O^OxO^Q^O^OxO^o'^O^Ox I-B30 NC 9                                      o Xj N3 z- .^ J 1 H A / X^oAn^AoTO<0 Xn^ °Or tn if OnAa h Me YAro n ° < o s H       Me°' fO0y 1                                      0 OH 0\ O^NH I-B31 \ HQ                                0 X\ / A';''NMe2H     ? H            JI  i rSO>^ONANY^^^NA¥ X j J h 1 o      q-X x° CN I-B38 I-B40 I-B41 I-B42 I-B44 I-B45 I-B46 I-B48 I-B49 I-B50 I-B62 OH I-B63 OH OMe I-B65 OH I-B66 OH II-B3 II-B15 MeO fj f ri             n^\ 0                                       9      H J            n naA H o . H o    fAW' AJ AyAV-W   0 OH ° V N              0       H Q       11 oXb-ob H          11 II-B16 MeO CXV°>^aJA o                           9 h [V4 J / N aA-   h 9 I h 9 ^'Ao n~ Nyb%HN AJ A^AAY^^    0 OH V N     A H A H O^N^°k H           11 II-B17 oCz ex o / A°° z \= /  )_J C \ ZI °b o ■ ZI A..... iz Ao A1 — /    o .A1 A“ Ao o o d A II-B18 z °x C\ °? ZI °=< o : ZI A.....    , iz         o _ / ^° ZI        o °b u i ( izv AA 9 Ao o o 2 o )    Ip / z          ° e XX^o    ( ) X         ) ° j-        ° <^ ° o ( II-B19 \ o >                      z <° XX: /        o—(Z / \ \"O °      s p          A° {                    0 d O          IZ $       A“° O             ZI b..... O          IZ (          A° ) °\ / "\ 0        y— / zi '^! “A II-D21 III-B1 III-B2 III-B3 III-B11 III-B12 IV-B1 IV-B2 IV-B3 IV-B4 IV-B5 IV-B6 IV-B9 IV-B10 O                                                       0           C-C KI ft                             X      Y H fl I H ft              1H A A AvAVAA A A) V      o H o H    UArV O^nX^Z,          fl / A 'OH H           11                                       = MeN^0 MeO IV-B11 \ AZ    Ph- kAt? P jA'A z / Z K o=<zAj Ae s o s ZI °1.....      , IZ         O ZI         o °=7     1 A AA 9 fo o o fl ov /             ° / z\             ° ( CAo    \ / I                /  ° A    o < o 6 IV-B12 \ Y~~P      PP- AAX? 1 X / AA Z /   '        O $ YA? Y1 * o ZI Y..... IZ Y° f Y <AT b d A H IV-B13 \ f— Z      O O / b / YYjq o b ZI °5..... z iz         o zi       b A...< 1 aAA °\ o $         P y-z        o / A / ^o    \ / |             ) o A-      o ( o X IV-B14 A ' o °4 7 -Y ° -“A ZI .....v= IZ - ___      o Q<>X <r ° AA \ IV-B15 r=Zy ? AAH—\ o o-YY " :\ A F° ^PJ 0s = o b ZI Y.....    , IZ         O ^=o ZT       b A.... 1 IZX AA °z o $         P A-z o / \ / 1                 / ° A-      o ( b X IV-B16 ■ ■-. o v X IZYp 7 -b     V—■ AZI .....X IZ S SQ fY-^° Z \^7 1 IV-B17 IV-B18 IV-B19 IV-B20 V-B1 V-B2 V-B3 V-B4 V-B5 V-B7 V-B8 V-B9 V-B10 \ HQ HN—v                                           ' Q , /   \ 'X_..0     A NH o                Hl xp      00 M    pPLAoVtQ fix       \ hP ^<Pp   0 p            z \ PNH         P 0                     v_0 °                       OMe V-B11 X   HO ?H0^A-.-'"^NMe2 0       H 9 H ? H    / NY^oAPQ Pl      0 H 0 L A 0              ' °      ° PP °               0Me V-B12 / x    N HN^            PJo Q .— / \                                     1 / P J^NH 0 0 Ntp      / °V^QmO p            / \ PNH         p O                     v_0 °                      OMe V-B13 \P° Pz o \ op ZI IZ 0^ ZI d^° op ZI < 0 / p' O^\^ / )—' 2 —L~< CD      / ^\ vJ . In certain embodiments, provided is the ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof, wherein the ligand-drug conjugate is selected from a compound represented by formula I-C: Ab 10 wherein: X, X1, X2, ring B, ring C, R3, R4, R5, R6, R8a, R8b, R9a, R9b, R10, M, Tr, L1, L2, and L3 are defined as described in any one of the embodiments of the present disclosure; Ab is a ligand that binds to a target; k is a drug loading and is an integer or a decimal from 1 to 16. In certain embodiments, provided is the ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof, wherein the ligand-drug conjugate is selected from a compound represented by formula II-C': wherein: X, X1, X2, ring B, ring C, R3, R4, R5, R6, R7, m, n, W, U, Z, Y, Tr, L1, L2, and L3 are defined as described in any one of the embodiments of the present disclosure; Ab is a ligand that binds to a target; k is a drug loading and is an integer or a decimal from 1 to 16. In certain embodiments, provided is the ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof, wherein the ligand-drug conjugate is selected from a compound represented by formula II-C: II-C wherein: X, X1, X2, ring B, ring C, R3, R4, R5, R6, R7, m, W, U, Z, Y, Tr, L1, L2, and L3 are defined as described in any one of the embodiments of the present disclosure; Ab is a ligand that binds to a target; k is a drug loading and is an integer or a decimal from 1 to 16. In certain embodiments, provided is the ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof, wherein the ligand-drug conjugate is selected from a compound represented by formula III-C': wherein: X, X1, X2, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R12, L, m, Tr, L1, L2, and L3 are defined as described in any one of the embodiments of the present disclosure; Ab is a ligand that binds to a target; k is a drug loading and is an integer or a decimal from 1 to 16. In certain embodiments, provided is the ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof, wherein the ligand-drug conjugate is selected from a compound represented by formula III-C: wherein: X, X1, X2, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R12, m, Tr, L1, L2, and L3 are defined as described in any one of the embodiments of the present disclosure; Ab is a ligand that binds to a target; k is a drug loading and is an integer or a decimal from 1 to 16. In certain embodiments, provided is the ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof, wherein the ligand-drug conjugate is selected from a compound represented by formula IV-C: IV-C wherein: X, X1, X2, ring B, ring C, R3, R4, R7, R8a, R8b, R9a, R9b, R10, m, Q, Tr, L1, L2, and L3 are defined as described in any one of the embodiments of the present disclosure; Ab is a ligand that binds to a target; k is a drug loading and is an integer or a decimal from 1 to 16. In certain embodiments, provided is the ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof, wherein the ligand-drug conjugate is selected from a compound represented by formula V-C: V-C wherein: X, X1, X2, ring A, ring B, ring C, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, m, T, Tr, L1, L2, and L3 are defined as described in any one of the embodiments of the present disclosure; Ab is a ligand that binds to a target; k is a drug loading and is an integer or a decimal from 1 to 16. In certain embodiments, Ab is conjugated to L1 by an S atom. In certain embodiments, Ab is a polypeptide, or an antibody or an antigen-binding fragment thereof, particularly an antibody or an antigen-binding fragment thereof, capable of specifically binding to a target. In certain embodiments, the antibody is selected from one or more of the following: (1) a fully human antibody, a humanized antibody, a murine antibody, and a chimeric antibody, (2) a probody, (3) a bispecific antibody and a multispecific antibody, (4) a monoclonal antibody and a polyclonal antibody, and (5) an IgG antibody. In certain embodiments, the antigen-binding fragment is selected from an antigen-binding fragment of a Fab, a Fab', a F(ab')2, an Fv, an scFv, an Fd, a dAb, a VHH, and a complementaritydetermining region (CDR) fragment. In certain embodiments, Ab is a monoclonal antibody, particularly a monoclonal antibody that takes sulfhydryl as a conjugation site, or a monoclonal antibody that has undergone site-directed mutagenesis or modification and takes sulfhydryl as a conjugation site. In certain embodiments, Ab targets an antigen selected from the following group: HER2, HER3, B7H3, B7H4, DLL3, TROP2, Claudin18.2, CD30, CD33, CD70, EGFR, GPC-3, ADAM9, BCMA, CEACAM5, and c-met. In certain embodiments, Ab targets an antigen selected from the following group: HER2, HER3, B7H3, B7H4, DLL3, TROP2, Claudin18.2, CD30, CD33, CD70, EGFR, GPC-3, ADAM9, BCMA, and CEACAM5. In certain embodiments, Ab targets an antigen selected from the following group: HER2, HER3, B7H3, B7H4, DLL3, TROP2, Claudin18.2, CD30, CD33, CD70, EGFR, GPC-3, ADAM9, and CEACAM5. In certain embodiments, Ab is selected from antibodies and antigen-binding fragments thereof against HER2, HER3, B7H3, TROP2, Claudin18.2, CD30, CD33, CD70, GPC-3, ADAM9, BCMA, CEACAM5, and c-met. In certain embodiments, Ab is selected from antibodies and antigen-binding fragments thereof against HER2, HER3, B7H3, TROP2, Claudin18.2, CD30, CD33, CD70, GPC-3, ADAM9, BCMA, and CEACAM5. In certain embodiments, Ab is selected from antibodies and antigen-binding fragments thereof against HER2, HER3, B7H3, TROP2, Claudin18.2, CD30, CD33, CD70, GPC-3, ADAM9, and CEACAM5. In certain embodiments, Ab is selected from tusamitamab, DB1001, DB1002, DB1003, DB1004, DB1005, cetuximab, and panitumumab, and biosimilars of the antibodies and antigen-binding fragments thereof. In certain embodiments, Ab is selected from tusamitamab, DB1001, DB1002, DB1003, DB1004, cetuximab, and panitumumab, and biosimilars thereof and antigen-binding fragments thereof. In certain embodiments, Ab is selected from tusamitamab, DB1001, DB1002, cetuximab, and panitumumab, and biosimilars thereof and antigen-binding fragments thereof. In certain embodiments, Ab is selected from tusamitamab, DB1001, DB1002, DB1003, DB1004, and DB1005, and antigen-binding fragments of the antibodies. In certain embodiments, Ab is selected from tusamitamab, DB1001, DB1002, DB1003, or DB1004 and an antigen-binding fragment thereof. In certain embodiments, Ab is selected from tusamitamab, DB1001, or DB1002 and an antigenbinding fragment thereof. In certain embodiments, Ab comprises the sequences of a CDR1, a CDR2, and a CDR3 contained in a heavy chain set forth in SEQ ID NO: 1, and / or the sequences of a CDR1, a CDR2, and a CDR3 contained in a light chain set forth in SEQ ID NO: 2. In certain embodiments, Ab comprises the sequences of a CDR1, a CDR2, and a CDR3 contained in a heavy chain set forth in SEQ ID NO: 3, and / or the sequences of a CDR1, a CDR2, and a CDR3 contained in a light chain set forth in SEQ ID NO: 4. In certain embodiments, Ab comprises the sequences of a CDR1, a CDR2, and a CDR3 contained in a heavy chain set forth in SEQ ID NO: 5, and / or the sequences of a CDR1, a CDR2, and a CDR3 contained in a light chain set forth in SEQ ID NO: 6. In certain embodiments, Ab comprises the sequences of a CDR1, a CDR2, and a CDR3 contained in a heavy chain set forth in SEQ ID NO: 25, and / or the sequences of a CDR1, a CDR2, and a CDR3 contained in a light chain set forth in SEQ ID NO: 26. In certain embodiments, Ab comprises the sequences of a CDR1, a CDR2, and a CDR3 contained in a heavy chain set forth in SEQ ID NO: 35, and / or the sequences of a CDR1, a CDR2, and a CDR3 contained in a light chain set forth in SEQ ID NO: 36. In certain embodiments, Ab comprises the sequences of a CDR1, a CDR2, and a CDR3 contained in a heavy chain set forth in SEQ ID NO: 15, and / or the sequences of a CDR1, a CDR2, and a CDR3 contained in a light chain set forth in SEQ ID NO: 16. In certain embodiments, Ab comprises a heavy chain variable region CDR1 set forth in SEQ ID NO: 7, a heavy chain variable region CDR2 set forth in SEQ ID NO: 8, and a heavy chain variable region CDR3 set forth in SEQ ID NO: 9, and / or a light chain variable region CDR1 set forth in SEQ ID NO: 10, a light chain variable region CDR2 set forth in SEQ ID NO: 11, and a light chain variable region CDR3 set forth in SEQ ID NO: 12. In certain embodiments, Ab comprises a heavy chain variable region CDR1 set forth in SEQ ID NO: 17, a heavy chain variable region CDR2 set forth in SEQ ID NO: 18, and a heavy chain variable region CDR3 set forth in SEQ ID NO: 19, and / or a light chain variable region CDR1 set forth in SEQ ID NO: 20, a light chain variable region CDR2 set forth in SEQ ID NO: 21, and a light chain variable region CDR3 set forth in SEQ ID NO: 22. In certain embodiments, Ab comprises a heavy chain variable region CDR1 set forth in SEQ ID NO: 27, a heavy chain variable region CDR2 set forth in SEQ ID NO: 28, and a heavy chain variable region CDR3 set forth in SEQ ID NO: 29, and / or a light chain variable region CDR1 set forth in SEQ ID NO: 30, a light chain variable region CDR2 set forth in SEQ ID NO: 31, and a light chain variable region CDR3 set forth in SEQ ID NO: 32. In certain embodiments, Ab comprises a heavy chain variable region CDR1 set forth in SEQ ID NO: 37, a heavy chain variable region CDR2 set forth in SEQ ID NO: 38, and a heavy chain variable region CDR3 set forth in SEQ ID NO: 39, and / or a light chain variable region CDR1 set forth in SEQ ID NO: 40, a light chain variable region CDR2 set forth in SEQ ID NO: 41, and a light chain variable region CDR3 set forth in SEQ ID NO: 42. In certain embodiments, Ab comprises a heavy chain variable region CDR1 set forth in SEQ ID NO: 45, a heavy chain variable region CDR2 set forth in SEQ ID NO: 46, and a heavy chain variable region CDR3 set forth in SEQ ID NO: 47, and / or a light chain variable region CDR1 set forth in SEQ ID NO: 48, a light chain variable region CDR2 set forth in SEQ ID NO: 49, and a light chain variable region CDR3 set forth in SEQ ID NO: 50. In certain embodiments, Ab comprises a heavy chain variable region CDR1 set forth in SEQ ID NO: 53, a heavy chain variable region CDR2 set forth in SEQ ID NO: 54, and a heavy chain variable region CDR3 set forth in SEQ ID NO: 55, and / or a light chain variable region CDR1 set forth in SEQ ID NO: 56, a light chain variable region CDR2 set forth in SEQ ID NO: 57, and a light chain variable region CDR3 set forth in SEQ ID NO: 58. In certain embodiments, Ab comprises the sequence of a heavy chain variable region contained in a heavy chain set forth in SEQ ID NO: 1, and / or the sequence of a light chain variable region contained in a light chain set forth in SEQ ID NO: 2. In certain embodiments, Ab comprises the sequence of a heavy chain variable region contained in a heavy chain set forth in SEQ ID NO: 3, and / or the sequence of a light chain variable region contained in a light chain set forth in SEQ ID NO: 4. In certain embodiments, Ab comprises the sequence of a heavy chain variable region contained in a heavy chain set forth in SEQ ID NO: 5, and / or the sequence of a light chain variable region contained in a light chain set forth in SEQ ID NO: 6. In certain embodiments, Ab comprises the sequence of a heavy chain variable region contained in a heavy chain set forth in SEQ ID NO: 25, and / or the sequence of a light chain variable region contained in a light chain set forth in SEQ ID NO: 26. In certain embodiments, Ab comprises the sequence of a heavy chain variable region contained in a heavy chain set forth in SEQ ID NO: 35, and / or the sequence of a light chain variable region contained in a light chain set forth in SEQ ID NO: 36. In certain embodiments, Ab comprises the sequence of a heavy chain variable region contained in a heavy chain set forth in SEQ ID NO: 15, and / or the sequence of a light chain variable region contained in a light chain set forth in SEQ ID NO: 16. In certain embodiments, Ab comprises the sequence of a heavy chain variable region set forth in SEQ ID NO: 14 and / or the sequence of a light chain variable region set forth in SEQ ID NO: 13. In certain embodiments, Ab comprises the sequence of a heavy chain variable region set forth in SEQ ID NO: 24 and / or the sequence of a light chain variable region set forth in SEQ ID NO: 23. In certain embodiments, Ab comprises the sequence of a heavy chain variable region set forth in SEQ ID NO: 34 and / or the sequence of a light chain variable region set forth in SEQ ID NO: 33. In certain embodiments, Ab comprises the sequence of a heavy chain variable region set forth in SEQ ID NO: 44 and / or the sequence of a light chain variable region set forth in SEQ ID NO: 43. In certain embodiments, Ab comprises the sequence of a heavy chain variable region set forth in SEQ ID NO: 52 and / or the sequence of a light chain variable region set forth in SEQ ID NO: 51. In certain embodiments, Ab comprises the sequence of a heavy chain variable region set forth in SEQ ID NO: 60 and / or the sequence of a light chain variable region set forth in SEQ ID NO: 59. In certain embodiments, the amino acid sequence of a heavy chain of Ab is set forth in SEQ ID NO: 1, and the amino acid sequence of a light chain of Ab is set forth in SEQ ID NO: 2. In certain embodiments, the amino acid sequence of a heavy chain of Ab is set forth in SEQ ID NO: 3, and the amino acid sequence of a light chain of Ab is set forth in SEQ ID NO: 4. In certain embodiments, the amino acid sequence of a heavy chain of Ab is set forth in SEQ ID NO: 5, and the amino acid sequence of a light chain of Ab is set forth in SEQ ID NO: 6. In certain embodiments, the amino acid sequence of a heavy chain of Ab is set forth in SEQ ID NO: 25, and the amino acid sequence of a light chain of Ab is set forth in SEQ ID NO: 26. In certain embodiments, the amino acid sequence of a heavy chain of Ab is set forth in SEQ ID NO: 35, and the amino acid sequence of a light chain of Ab is set forth in SEQ ID NO: 36. In certain embodiments, the amino acid sequence of a heavy chain of Ab is set forth in SEQ ID NO: 15, and the amino acid sequence of a light chain of Ab is set forth in SEQ ID NO: 16. In certain embodiments, Ab is an anti-CEACAM5 antibody or an antigen-binding fragment thereof, e.g., tusamitamab or an antigen-binding fragment thereof or a variant thereof. In certain embodiments, Ab comprises a heavy chain and a light chain of the anti-CEACAM5 antibody or the antigen-binding fragment thereof, wherein the amino acid sequence of the heavy chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 1 or is set forth in SEQ ID NO: 1, and the amino acid sequence of the light chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 2 or is set forth in SEQ ID NO: 2. In certain embodiments, Ab is an anti-HER3 antibody or an antigen-binding fragment thereof, e.g., DB1001 or an antigen-binding fragment thereof or a variant thereof. In certain embodiments, Ab comprises a heavy chain and a light chain of the anti-HER3 antibody or the antigen-binding fragment thereof, wherein the amino acid sequence of the heavy chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 3 or is set forth in SEQ ID NO: 3, and the amino acid sequence of the light chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 4 or is set forth in SEQ ID NO: 4. In certain embodiments, Ab is an anti-GPC-3 antibody or an antigen-binding fragment thereof, e.g., DB1002 or an antigen-binding fragment thereof or a variant thereof. In certain embodiments, Ab comprises a heavy chain and a light chain of the anti-GPC-3 antibody or the antigen-binding fragment thereof, wherein the amino acid sequence of the heavy chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 5 or is set forth in SEQ ID NO: 5, and the amino acid sequence of the light chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 6 or is set forth in SEQ ID NO: 6. In certain embodiments, Ab is an anti-ADAM9 antibody or an antigen-binding fragment thereof, e.g., DB1003 or an antigen-binding fragment thereof or a variant thereof. In certain embodiments, Ab comprises a heavy chain and a light chain of the anti-ADAM9 antibody or the antigen-binding fragment thereof, wherein the amino acid sequence of the heavy chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 25 or is set forth in SEQ ID NO: 25, and the amino acid sequence of the light chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 26 or is set forth in SEQ ID NO: 26. In certain embodiments, Ab is an anti-BCMA antibody or an antigen-binding fragment thereof, e.g., DB1004 or an antigen-binding fragment thereof or a variant thereof. In certain embodiments, Ab comprises a heavy chain and a light chain of the anti-BCMA antibody or the antigen-binding fragment thereof, wherein the amino acid sequence of the heavy chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 35 or is set forth in SEQ ID NO: 35, and the amino acid sequence of the light chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 36 or is set forth in SEQ ID NO: 36. In certain embodiments, Ab is an anti-c-met antibody or an antigen-binding fragment thereof, e.g., DB1005 or an antigen-binding fragment thereof or a variant thereof. In certain embodiments, Ab comprises a heavy chain and a light chain of the anti-c-met antibody or the antigen-binding fragment thereof, wherein the amino acid sequence of the heavy chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 15 or is set forth in SEQ ID NO: 15, and the amino acid sequence of the light chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 16 or is set forth in SEQ ID NO: 16. In certain embodiments, k is selected from integers or decimals from 1 to 10. In certain embodiments, k is selected from integers or decimals from 2 to 9. In certain embodiments, k is selected from integers or decimals from 2 to 8. In certain embodiments, k is selected from integers or decimals from 4 to 8 (e.g., about 4, about 4.5, about 5, about 5.5, about 6, about 6.5, about 7, about 7.5, or about 8). In certain embodiments, k is selected from integers or decimals from 6 to 8 (e.g., about 6.1, about 6.3, about 6.5, about 6.7, about 6.9, about 7.1, about 7.3, about 7.5, about 7.7, or about 8). In certain embodiments, k is selected from integers or decimals from 7 to 9 (e.g., about 7.1, about 7.2, about 7.3, about 7.4, about 7.5, about 7.6, about 7.7, about 7.8, about 7.9, about 8, about 8.1, about 8.2, about 8.3, about 8.4, or about 8.5). In certain embodiments, k is selected from integer or decimals from 7.5 to 8.1 (e.g., 7.81, 7.82, 7.83, 7.84, 7.85, 7.86, 7.87, 7.88, 7.89, 7.90, 7.91, 7.92, 7.93, 7.94, 7.95, 7.96, 7.97, 7.98, 7.99, 8.00, 8.01, 8.02, 8.03, 8.04, 8.05, 8.06, 8.07, 8.08, 8.09, or 8.10). In certain embodiments, k is selected from integers or decimals from 7 to 8 (e.g., about 7.1, about 7.2, about 7.3, about 7.4, about 7.5, about 7.6, about 7.7, about 7.8, about 7.9, or about 8). In certain embodiments, k is selected from integers or decimals from 7.5 to 8. In certain embodiments, k is selected from a number from 2 to 8, e.g., 2, 3, 4, 5, 6, 7, or 8. In certain embodiments, k is selected from 6 and 8. In certain embodiments, k is selected from integers from 1 to 10. In certain embodiments, k is selected from integers from 2 to 8 (e.g., 2, 3, 4, 5, 6, 7, or 8), e.g., integers from 4 to 8 (e.g., 4, 5, 6, 7, or 8), e.g., integers from 6 to 8 (e.g., 6, 7, or 8), e.g., integers from 7 to 8. In certain embodiments, the ligand-drug conjugate is selected from a compound represented by formula I-C-1, II-C-1', II-C-1, III-C-1', III-C-1, IV-C-1, or V-C-1: R9t! R9a C (R )m R6 l_3-Tr p12 ' A N~Tr R8b R8a R8b R8a 5 wherein X, X1, X2, ring A, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, R12, m, n, M, 10 W, U, Z, Y, L, Q, T, Tr, L1, L2, L3, Ab, and k are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the ligand-drug conjugate is selected from a compound represented by 10 formula I-C-2, II-C-2', II-C-2, III-C-2', III-C-2, IV-C-2, or V-C-2: wherein X, X1, X2, ring A, R3, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, R12, m, n, M, W, U, Z, Y, L, Q, T, Tr, L1, L2, L3, Ab, and k are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the ligand-drug conjugate is selected from a compound represented by formula I-C-3, III-C-3', III-C-3, IV-C-3, or V-C-3: 10 wherein X, X1, X2, ring A, R3, R4, R5, R6, R7, R8b, R9b, R12, m, M, L, Q, T, Tr, L1, L2, L3, Ab, and k are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the ligand-drug conjugate is selected from a compound represented by 10 formula I-C-4, II-C-4', II-C-4, III-C-4', III-C-4, IV-C-4, or V-C-4: R8b Ab—। L1 3'Tr 4-(R7)m V-C-4 L< R12 HO R6 III-C-4' wherein X, R1, ring A, R3, R4, R5, R6, R7, R8b, R12, m, n, M, W, U, Z, Y, L, Q, T, Tr, L1, L2, L3, Ab, and k are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the ligand-drug conjugate is selected from a compound represented by formula I-C-5, II-C-5, III-C-5, IV-C-5, or V-C-5: III-C-5 Ab--L1 V-C-5 wherein X, R1, ring A, R3, R5, R6, R7, R8b, R9a, R9b, R12, n, M, W, U, Z, Y, L, Q, T, Tr, L1, L2, L3, 10 Ab, and k are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the ligand-drug conjugate is selected from compounds represented by formulas I-C-6 and I-C-7: I-C-6 I-C-7 wherein R1, R31, R5, R6, R8b, R9a, R9b, M, Tr, L1, L2, L3, Ab, and k are defined as described in any 5 one of the embodiments of the present disclosure. In certain embodiments, the ligand-drug conjugate is selected from the structures shown in Table C: I-C13 I-C14 I-C35 I-C46 I-C47 .............. \         OMe                        / I-C48 NMe2                                    \ J H 1 o       / -7 F................... \             OMe                                 / '                                                                                      / k I-C49 /       »y~“                  \ 0    H      ?  H             ?   \ i.j^Vy rs a.......... y>- - A........ \             OMe                                  / x                                                                               / k I-C50 / . \ j i h 1 o vr...........-? \             OMe                                 / x                                                                                / k I-C51 / \ ?HOV L 0       . 0 H            ?   \ 1 n^XAoVJLJ H 1 0 VJ...........a \             OMe                                 / x                                                                            7 k II-C2 6H OSl III-C13 IV-C1 IV-C2 Ab— 1 X o          h 9    h   o—A"0H J<        ^NY ¥ i Ya° \Vk    o a 0 MJ Y \              X             X / / 0Me \           HO 'O             A> X                                                                  ' k IV-C3 Ab /     X ' Xaoh o            H O     H 0 / OH n.       N-.AA ■A N^^^^X ■ nM Yit vo \ XX     0 x HO       Y \                 1                AT eN-     / \ O         X              L II OMe / \               HO 'O                  A            / X                                                      / k IV-C4 Ab 1        Ao \ Xa oh O           H O     H O / OH N    Z\ZNKZA>< Yr; A i HA AjVy0 \             J            / Y eN- / \ O          X               L II OMe / \            ho'o             A         / X                                                      / k IV-C5 Ab— /     CA \ 9         H 9 H JK"OH Xa> Y ""^     aMXT X i X^ 'Y \Xa     o a h O MJ Y \            r           A>n, / \               X              Y / / 0Me / \          HO A          AA      / '                                                                             ' k IV-C6 IV-C7 IV-C8 IV-C9 IV-C10 Ab^ 9                         A    °AN \ nAA h 9 i h 9 AA° ih A \ AJ A-vA-vAA A n o h o h    AAV o^An-'n        VAA^ ah \                  H                     MeN"% \                                                         MeO               / X                                                                            / k IV-C11 Ab- o     n'A   \ Z-A                    / x.    A       rN    \ _AA h 9 I h 9 rir 0Ah  A ______________'   x-n / .xnA.,9^      A 1    1 AS ---SA: nA        J / 0   0 A   0 = H      IhAn-x r                ^ya-oh0 °AH          FVAoh \                                           MeN-% \                                                       MeO              / / k IV-C12 / 1                A \ h 9 i h nn° ih A \ AV           A / A N              II £ H II £ H               19 VA Abq       (        Aay \                   0 N-b-0^                          ’'OH      1 \                   H                      MeN-%         / A IV-C13 Ab- caA O^^JQ, o b ZI A.....    , TZ         O zi        o A.... aV^v s o )    Ao r z         ° ( t. A^o ( / \ ) ° \ ° ? \           ( o IV-C14 / 9             a yN \ ifA / H 9 I H 9 YA° ih A \ Av AanAn\n^n^ A / j a     T      aa°h^ \           o^nW0^         AA^'"oh / / k V-C3 V-C4 V-C7 V-C8 V-C9 wherein Ab and k are as described in any one of the embodiments of the present disclosure. In certain embodiments, the ligand-drug conjugate is selected from the structures shown in Table E: I-E2 NC \ 0 / ¼ \ /     nA^N-I     h 9 I h 9      £ /     n \ 0 / - H 0   = H Me            / / Tusamitamab-r                 £          MeO'NyV%^ \                     O^NH                0 OH Ox \     -'''O'''" \ \                                                                 / k I-E3 /             1 h aY_ / yJX    Me       A\ / N^y           3—-Tusamitamab N^X^oAAQf J M 0   0 / V° i ■"" I I-E4 'p ......' ©A ZI O / "'( V / =° “ o“ u a IZ w 0=4   / C-x 2 —c Xq z A 'Tusamitamab I-E5 °~A o-A / )—-, z ^=\ 'rQ 4 z>sz. Ay'0 b ZI 0 o=( o b ZI °-)..... IZ ZI / z -Tusamitamab I-E6 / o 4° IZ )-\ P o=(     \ a IZ °s 0>    \ zs C 7 o=^-, / 7—< r v-o 7 \= / z A Tusamitamab I-E7 / >1K- ? « fi AvUofyj h ) o   x7 v.....b X                                                                   / k —-Tusamitamab I-E8 / VUr H o h V>\ n A JL All 1     N H L O     0 / 0-. / ^--.^) / H J      o      \ o \                               A            / \                            O^OH \         CN                      4 'Tusamitamab I-E9 /                           H0^ / 0                \ °hoH°-      -0Me      0      - 0 lH0\ / Y N H     H H : II     / kzNx / \ / 44\ 1 Me M N 1                 YH          o N,;                      1 H \    Q \          OMe                              / Tusamitamab / I-E10 \>^0 / / z ° \ o=\ ZI yV >o S o“ u ® IZ °' °4^x ZS C 7 °^- / A-x / —\ / / )-° g” yvA jQi y° z A 'Tusamitamab I-E11 /                          HO^.0                \ H° JL / OMe 0   < o     V)\ f TyU<arA1 1 / A^o<Yj o H ° V':..........0..... \ CN / k Tusamitamab I-E12 °^\ )—\ -z. \_ / / o \     (D ZI O \__ o ZI XT ^Tusamitamab / I-E13 / T°sX h J H / / / / I \ N^J^oVY I 0 H J 0 \V° Q    HoX          / \ / k Tusamitamab I-E14 1 O--N If V          > o J H 0 = H Me Y\[ fX Tusamitamab'                         (              .._^N  \ / \v^ X       Me i xxx \                            O NH                    0 OH 0            / \ / I-E15 NC \ °                       x>       \ XxXjJ -UXa \ T -t                                                    H 0 Tusamitamabl                           (                       A / X < A                     ; 0HA \                     O^NH                   OH °x \ \ ° / ^ \                                                                / k I-E16 NC \ /                                      o XX            \ 1__ XnXNXn--X h X / aXX / A TusamitamabH        X>       O 1 H o i H         MeoX'-X^X'' or            Hl OH* \                        xX                                O OH °\ \                    O^NH                                             / \ / I-E17 /                                                   NC          \ /                   / O                                 °        U J            \ h 9 । h ? rv^oAAA vv\JX nxnv ° s frtxYv Tusamitamabl-            0     0 > H o    H        MeO'YXX \                         JL                                 O OH °\ \                     O^NH                                              / \ / k I-E18 NC \ 9                          0 XX        \ ixn h ? i h ? xAaaIxI) X——"X^   x ■^^n''XnX^nXX h XeAVXX / '1'1 Tusamitamabl"                   =  H     ;  H        MeO'NyVy> \                       Jl                               0 OH °X \                     O^NH                                              / \ f^o^x-o'^'o-^-°X \ °-^o^X^°^X^o / X / Ox^ao / ^O^                          / k I-E19 NC \ /                                      O XX (fx        \ 9       h 9 i H 9 AaX X JL 1    X !____X^N-^-^-XfN'^N'\fN'^N'X=>'    h'^XXaXXX”^1 TusamitamabH--\l        J H    = H        Me^yAX or                 ii - oh* \                       A                               0 OH °x         / \                    O^NH                                             / \ 0                                                           / k I-E20 NC \ /                         0                                            O          fi 3                \ TusamitamabT               0      O > H 0  = H           Me' Y'AShT \                          /                                 O OH °x \                   O^NH \       A        J                                   / \      0          0 \ O.                                   ,o. \      o          0          0                                                 / k I-E21 ?                               O ^X ( /     N'^f' TA   H ? ! H ? FY^oYAX Tusamitamab-p^                  0^ H O     H           Me"N^"^ \                              /                                      O \                   O^NH \    °—o— c           \ Vy-A \ AV* N ; ohT          1 OH °\          / / k I-E22 °x 4W"° O^\^ /  )---. / =° V-^'” b ZI o °^-o IZ o ZI Ox / LYo —Tusamitamab I-E23 °x H?Z O4W'5 s / =V'r° VY b ZI o °5 IZ o r ZI ox / .......... T, \—Tusamitamab / I-E24 >^VMH    H     F \ o H J ° \                     O^OH \ CN / x                                                                              / k —-Tusamitamab I-E25 >^°S / 0MH     H         \ rvvLX<NxYN^NA^^^jLrn N ;; A       j J U 0           , vA - i —Tusamitamab I-E26 / NX *1 Vo 0                  H ? 9 H              9 \ XX“Bv°ZY o 1 o 0Y Y T o HoX                    \l ZX               if                                     KT ., . \ /               0                                         Tusamitamab CN                                                 / / k I-E27 Tusamitamab' OX Ox Vz ZT °X & ZI Y.....    , IZ         o z ? zi        O IZ X--X ) O Vo o o ) X ° V-z        o ( \ °? \ I-E28 Tusamitamab' /                                                   NC          \ u                                             0                            \ Lx / XYAVAXYAb^ 0 A 0 = H          XhY J                                         OH 0x \                     O^NH                                              / I-E29 Tusamitamab' / .:i / / x iTNXN^N fOiO H mOxOO' o     0 r= H o £ H         MeO' Y'VXhT f                                  0 OH O\ \                     O^NH                                              / \ Zxo'^ / O'- / xo'^x / OX \ °          /                                             / k I-E30 Tusamitamab' NC \ /       ?                      0 r^xO    ^x\ ' jTY1 NX / xX 2 I n 1 yv^aXaYo^jq __——X oxr xx AX h MeYxZj / N 0 A   o = H      Meo' y V^Y 1                                    0 OH °\ \                   O^NH \ / \ o / o-'z° / x'. / o / o                         / k I-E31 DB1001-T NC            \ 0                       0     fj        \ H n I H ? YVXoXnAJLXo_ A ——    VN''AfN'^M             H iFCyXJ' n o    0 > H o = H       Meo' / Air J                                    0 OH 0x O^NH                                         / Zo''' ''°'''O'' ^                                                       / 0 , / 0z' x0 . / Q                                                        / k I-E47 N n N      YVi N^J^ / QU 0 H 1 ° V”                J -DB1003 I-E48 /          HoMe2N     H2N                            \ /     OhOxA""   0^= OH        0 X    N'^ N     N '           N --- NV^^OKA J 0 H   0    0^ \ 0 \        "CN                        / XDB1003 1 I-E49 /    x HQMe2N    H2N                         \ r..........A      / x                                                                                    / k —DB1003 I-E50 ....................A; z.........Q         / x                                                                                  / k -DB1003 I-E51 fTWYBZANz"YLZn N^J^oVX J 0 H J 0 \ ° X °^°H x                                                                              / k —DB1003 I-E52 /                                   = o                9 / AAA'" NMe2H n XX O ” * O      >Z / sZZpOZ \ \            CN 1--DB1003 ). I-E58 NMe2                                     \ J h i o v°                    / \             OMe                                  / x                                                                            / k YdB1003 / I-E59 ?ho^-         z o H          j \ A,          .......'-7H VJ  i?                / \             OMe '                                                                                             / k ^DB1003 I-E60 NMe2                                    \ ..............i?......                1 \            OMe                                / '                                                                                       / k —DB1003 I-E61 /         N^^OH                      \ n^JM-o-VT J J H 1 o \ M Q \               OMe                                      / DB1003 i k I-E62 / , / ^°z \ ?"oxA ° H 5 ? H          A \ .,ajjW.......'jM-\2...........i?...... \             OMe                                 / x                                                                               / k -DB1003 I-E63 I-E64 I-E65 I-E66 I-E67 I-E73 o o m Q z—k $ ° o o o4 I          / ZT o         ( o         \ O           > T H g § t5 IZ xa \      \— / o \      / b-x Vz^OAj oXM / x^ / I-E74 w' oXXP^i x— / ° s?         ,--<           w O     / ^X X ZI M o w iz o—( Vo r t IZ        1 o o Ox Y-z X / ^0 o w o I-E75 O-X r^X°X / X / ¥u zi / — / °^\ 0      / ^\        / M ° ZI M 0 by IZ O—<  )"O > H 1 ( 0 > I IZ        1 7 0 0 Ox LXo u 0 I-E76 /                                  OH                             \ HOV / >COOH                   \ \          y"0      Hoby°                   \ Jb%<i0 h r'b00        0 \ / V^°5bXJ 0     H H 0                   0 / \            OMe                                           / z k I-E77 /                                   OH                             \ HO^^x^COOH                  \ /       / ZV HoX°             \ b4°vx0 h cr°00        0 \            OMe zk I-E93 /                                H ; o H             9 \ xn H9                                                    ---DB1004 1HOX / ^ '               [1 | n H i A           X- / \ ° • 7 \             ON ' k I-E94 /                         h2n^o                     \ ”1 \ NMe2                     H . 0 H               J? \ ^O    \                       s / -'"N' \-----DB1004 \            OMe                                        / k I-E95 / \ HO                 _ \ ?HOk              z 0 H             S \ AyVoAJU I H 1 o \ ..........O \             OMe                                 / x                                                                            / k I-E96 /                                  OH                             \ ho^A^coqh                \ /           HO                H0' X                              \ h rr oo      ° \ / v^oWL J S    H H \^° Q                   0 \           OMe                                          / f k I-E97 HOMe2N     H2N                         n \ /     °'OV      O^ OH         ?  \ N". N      N •               N         - DB'004 . N^A^oVjfj SHO    o / V4.........Q x                                                                                          ' k I-E103 /            „0^“»         \ / 'A       hc3y°                  \ h cr°°°       ° 3 H H         a7 / ” s \            OMe                                             / k I-E104 /                                  OH                             \ HOV / .COOH                    \ ,NMe2            HO" Y°                            \ ?hoA^ h rv0°    °           ° ImVvY N           N            -J—DB1005 / yWkJ I S    H H \ ^° Q                      0 / \           OMe                                          / ' k I-E105 /                           QH                       \ H0v,,.- ^C00H                         \ /         / -Y'Y      ho-^Y0                   \ 0 h nr°5 5 AyWQJ S   h h ” • \             OMe k I-E106 /                                   OH                              \ ho^Y^gooh                \ ,NMe2            HO" Y°                              \ AX I n oAAX^X^^o^Ji N.AAAo'Of J S      H   H \^o Q                   0 \            OMe                                           / 7 k I-E107 Az Jr\d^ /  o^\ ®     / ^X        / zz °A o IZ  O— /  )"O Vo     - (         ° >        I zz        1 o o Ox L^° c cn 0) 3. S’ 3 CD I-E108 ID O s Q 0== / 1 zA $ ° O O =4 O          > O..Q-0 HX °>° IZ xp   kA (  ~   \-J     O \^°   /     s /   / —( r\-o k ° Xb y° z ^Z I-E109 /               HO^OOOH           \ /       A /      HO'k°                \ Ab / ° h fA° 9 $         X f rV':rN'                                  --— DB1 002 AyVol (J £    H H       A / • " \            OMe ' k II-E1 / In                          111^ / / / \\    / ^y                                           , f.            N-- / ’^Tusamitamab Xo'\z \\ oh OH                       ~~~ /     -y---      \ 7>V \          X                          hn7 \                         H hb°                 / '                                                                                    / k II-E2 Tusamitamab z °k >ko / oy r \ )-1° CD \—- /   )__ / 5     r—f   '■ C\ 7=0 Vy / T^ ZI o=>..... IZ -V f o< Z 2=0 o o d II-E3 Tusamitamab^ /                                   MeO            \ CaM^x ii \ y~l     H 9 ! H 9     H / H / / "N 1       r £   h n s   H       Zi    - ohi \ o       O ;   H O =   H      O   OH <\ \ 0                      z II-E10 — MeO           \ o                 9 h / vX I                            ,- A ^n, ,(, AAA nAA^na H 9 I h 9 nC° h V °HA AJ                              o oh ox X             o > h s h                               / \    4x            / / II-E11 Tusamitamab—- /                                                          MeO            \ \             Ji XxXa L^-^AaAXT0 »A''0A '—0 A H o = H 0 X \                    O^NH                                                  / II-E12 /                                                    NC          \ o                  \ __,0                          U     H / AI         \ X——CC^X is a XX0 Y'Xf Tusamitamab-4     ~             X           ;                                       0 OH O\ 0      o A H o £ H \                    O^NH                                                / \ ^^^O^^XX^            / x                                                                                                     / k II-E13 — ■             A '                          OCX'aaai \ I          aa- a XOxev N iA'A H ? 1 H ? nc° h ^1' °HA XJ X'VA'XX    0 OH 0x X             o > h s h                               / \     °Vx               / / II-E14 £D 3 S’ 3 H I 0 A X 0 ( P O oX O (     K ZI $ vA'A O        IZ J =A O         ZI '    .....A IZ -o IZ X ■-XX s / (    / ^X CD °L'yX° O< / ° / O vy Xz vX II-E15 MeO             \ AU H 1 H              N^\  \ X ' O         J O                     An HVaJ / n N^Xi NA     h O 1 h O f"'X''"O N""^ Y XOA ..           o     N ' nnn               H        O OH O Jr N           0 > H 0 = H Tusamitamab \                            f \     Ov-^ '                                                                                                                           / k II-E16 c w CD 3 S’ 3 O’ Ho p o o o=( >a r IZ   X""< 1 X° o ZI "A IZ -o IZ oH \—, / -___.   2 / (                n> oHa AQ II-E17 NC \ /                      CI^-^vaX^ ?                     J. Hfx-X ^Hr Nn h ? । H ? HiC° ^nJ"HHhn A / HvAV-W   0 0H Jr                o > H o 1 H                                    / Tusamitamab \                            A \       <Aa °x \                                H         11                                                                  / / k II-E18 DB1001- / 4 l. / H ) LH ° Jka O        IZ I A O         ZI '    .....A o lo So<AA° o A0 y-o Z\r=^ II-E19 - HO O      H rXr JL     ° H °^0H OMe                            / / k II-E20 x HO 9                                           Q.     \ ^Ov UY    ? H ■ 9 H   9     Ya \ Il YY / A / X 0 H    Yu       H          v AdB1001 sAAlI j     °    °       0 \          Ax' \            CN                                             / \                                                                                           / k II-E21 MeO           \ I          / ^Y / ^Oayy N ^Yt n h 9 । h 9 Yli 0 h 9i' °ha X J Y. / znA^An-A.iYx       o oh o nV  0YYnyYn^       x DB1OO1^y          0X0-                        / \     A^°l / k II-E22 u cd > < r>° < O   Yz •. • c _ ( p o o=( o ( y—\ zi $ : "A O        IZ X O         ZI '      .....9o IZ -o >=° IZ An O= / \— / Y^ZY—s s / a An <u s^AX0 mo II-E23 . A 9 ,°                 II   H / \X Mn _ / Y h 9 f h 9 YX^°^N^^NV'YYvr _____—-—"AY     n u A n a A J     H fi : oh! DB1001-----Y ^Af - bl Yr 'Y'A          0 OH 0x 0     OX H     a H \                   O^NH \ po^M^Y                 / II-E24 o CD H= p o °. A MxZI 7 A° ° o=( Y IZ - o Y° IZ O=(  \—- / S’" 0x0"" oYY 7°^y MO II-E25 DB1001- /                                                       MeO           \ » c^r.r) \ ,0                               II      H YAI / / N I \                  O^NH \ po^0^'^0'^                         / \O^OZ^O^OZ^O^OZ^ II-E26 DB1001^ H= p o O ©X ° v■ o=( ZI .....A IZ - o IZ O= /  \—_ / /     1                    n> si"VW 0XL / 0 / O V / Yz II-E27 DB1001^ MeO           \ 0                            2 H (x-X nW h ? । h ? nc0 !CntXv 0A AU UU \    Aw, '                                                                                                      / k II-E28 □Bwor °'X? CZT a-T^i z \=y J— / <T\ A=° ZT 0 b ZI ..... IZ Vo -V — /   0 oU Z <u ^0 0 0 k II-E29 DB1002- /                                                          MeO           \ / o \ _z0                  u   h / VXj n \ J n 2 XjV h^nx —       y '~Xr                      0 oh ox 0      0 0 H Z      H \                    O^NH                                              / \o_o^zo^o^o_o^ II-E30 - vY O      H          N -o hU^VbYA^ ° ayv i     o a AAc / OO    A°h OMe / k II-E31 x ho 9                                           Q,     \ ?hov xYN^ ? VY 9 h 9     Ya \ aW SZ 1 V-K a\ -¾ / A       / \ / Y       N^ / \J li            0 h YN Yu          " Ydb1002 oAYYoAYY j   H    o H    o H         o \ L-n     aA                                       / \              CN \                                                                                           / k II-E32 o-A A / AY o- / YY / ',i° <D V—J 1__ / 5 ,- / '■ Ya 7=0 Ya1^ °A o ZI A..... )=° -^-oW" I <MZI o d A o m Q II-E33 /                                                        MeO           \ /                    o Qjy'taV \ u h r\A r N o     H o ।  o ArAA^AAvV DB1002-—.L     k / \ / \ / \NAANAXJ   H   " i0Hn | ——x^nxyn'^            0 OH 0\ o / H 0     H \ 0 1 \                    O^NH                                                / \                                                                                      / k II-E34 DB1002- . A. 9 ,o                 ii   h / YT YA _ / Y h ? f h 9 YYAYN^^Nv'YAAr _______A N ,-. N A A N A A J      H     fl i OhI ---Y ^Y AA^nA     0 OH ox 0      0 > H 0  = H \                     O^NH                                                / II-E40 DB1003— NC \ /                            o Ci ---CT-jTw 2XjT° O      O > H 0  = H \                             CT NH \ ^0—°—0^ \ O . ,^                                                    / x / II-E41 DB1003 / O / 'o'-' / O / ^                            \ s                                 \ HN^O                       Me0 jivTn     ; Vy, h a « s Yayy \    0                           Y ' L 0¾ \                                o     0H 0x         / II-E42 DB1003 OH                            \ /                      H00C-, JT°H                       \ °^OH    O - OH    in Y     o^ 0-. / -     YA V°><=x Y- I? I? Y1    MervX / / N? \ V4             H    H       n     6h 0¾ \      0                                              x \                                                                                 / k II-E43 DB1003- /   .....Y Y Y / -X      A 2 o               0     0 p |l Me2 / A J An A     "  "    0HY \                                                                     / k II-E44 DB1004-- NC \ o ———J nJ XT"0 ^vTTj Y '“Af ''-AAY'-A^Y        o oh ox O      0 > H  0 = H \                        CT'NH                                                        / \               "°n X                                                                                                    / k II-E45 DB1004— / °S                                                 \ HN^                      MeO               I 9      9 | H 9 I H          fY] CP      O-A l / n-^n\n^n\ny> UQY^vyA \ \ A     H n ; H n Al     Me 7x2 II N \    0                       Y ' - YY \                                    o      OH Ox           / X                                                                                              / k II-E46 DB1004 OH /                             HOOC,, / L ,'OH °-Ah   Y I 9           J ?°T1 0 Me Y A    / O / yNZ / 'NX'   A \ Y                ° MeO             \ A ■ OH °\ / k II-E47 DB1004- I ” Y, Y . lY'r^x Y<> / q                       9        9 Y ll Me2 / \       li n Y K          A   A / A A _n^ .1 AY> VY 1                       Y \Hr \                        H      H              OH 0         / \ 0 / x                                                                                     / k III-E1 /  AAs \ / > ""A ‘ A™ \ Tusamitamab— Wn         xo,,„ \ JYA / i'' °H y                    I \ 0Me / k III-E2 \MeCX A                              \ A      /                            Y ' YVO                LI      ^A- ii                               A.         , n / AX OH 0           HN         A ryJY X      oAL /     o o / ^n 0 A o An" Ay QH0        ( HhT H2nX               / / k . Tusamitamab III-E7 /                  'to^Jy0    \ H 7 fi H ? ?          / ? \ ^ny^n^ny^n^nA1 o^-o^jlp o h * o h pp r NH ■ -Tusamitamab III-E8 /                                        H            \ To^y0   \ h t 9 h 7 9       9 \ p / p^ ooPP o H 1 o H pP^ P                   0 zNH \ ^y^pn \ / \ Po P / >                         / \           OMe                               / x                                                                                         / k —Tusamitamab / III-E9 /                                        H            \ pj^y0   \ h      9 h ■ 9       ? \ o o^ /    0 H i 0 H pPP P                   0 zNH \ PPp^i ^0H \ / V'UpOpj \ V°     P^s                         / \           OMe                              / x                                                                                        / k —DB1001 III-E10 /                                        H            \ H T ? H ? ? / ? \ °;z0 / ^ 0 H i 0 H   pPP 7                            o zNH \ PPp^l ^0H \ f "pppp            / Pn q             / \           OMe                              / x                                                                                        / k —DB1001 III-E11 /                                        H            \ h = 9 h ? 9       9 \ 0 0 ,,-       0 H I 0 H A- / | 7                               0 zNH \ \ Vo \            OMe x                                                                                        / k —DB1001 III-E12 /                                        H            \ H 1 9 H ? 9       9 \ 0,0, /     o H 1 o H 7                            o / NH \ ^0H \ ayWulJ \Vo \            OMe x                                                                                        / k „ DB1002 III-E13 /                                        H            \ To^y0   \ H ? 9 H ? 9       9 \ o H 1 0 H 7                            o zNH \ f v^Qpo Q             / \           OMe                              / x                                                                                        / k „ DB1002 III-E14 /                                        H            \ To^y0   \ H ? ? H ? ?       9 \ ^ny^n^ny^n^nAA o H l 0 H 7                            0 / NH \ rN*^XX \ Ay^o>jLJ                / \v°   yA \          OMe                             / x                                                                                        / k „ DB1002 III-E15 /       d.       vA /                    ? H - ? H ?        A \\ x ( I H A H S H             & 0 1¾ \            OMe                                            / '                                                                                                               ' k DB1003 III-E16 /                         °Ya\ \ rN^NO °^V     ° \ A / \         T            h2n^o                  / \ Meo / k ~DB1003 III-E17 \     H     ?        H     H              TA / \ rN<NA ' „ AU 1 UJ I     1 i               HOn \             M               HO'' j- 'COOH                           / \ 0H \          MeO                                                    / , ' k DB1003 III-E18 / x H         „„X^X^t / A \     ?ho r 'OkTk °°yV      0 1 / -¾ A / \      mJ        h^n^° ' k ~DB1003 III-E19 / NxJ VY /        Q \\ /       A—< _     HO. 0 kiH  Tj \                  r 1]               HO'-       "'COOH \      V         OH                   / \         MeO                                              / / k ODB1003 III-E20 oCz / M Mt, _ZI M —z >° o V V- / o J \ p z~ / " DB1004 III-E21 / °\_. \ \    dll       H    H            1 A 1 „ MXS 1 uj °        ° ' ।          M          i \              r 1] x^7          ho'' Pooh \                              OH \          MeO                                                     / , ' k — DB1004 III-E22 /    x    h x M X / \       MeO ' k "DB1004 III-E23 / x N       H H        Xv\ /   >„0 f rAXrYT^NY^0^^ I N ry / S     ay o o         o l    Jjx H°P \             C J           HO'> kY ''COOH                            / \        T           OH \        MeO / k DB1004 IV-E1 / % \ °          h ? h rx-'°H Tusamitamab^L / N              ■ N Y P T 'r --^O o > H o MJ X \    p         1              MMeN, \                      L                    A / / OMe \         H0 0          V ' k IV-E2 Tusamitamab — 0        H ? H JX0" X /      'XX TTyv0 \yy    o y H o UJ y \                 1                yxWeNx \               X              L / / °Me / \             HO O                          / ’                                                                                            ' k IV-E3 Tusamitamab-— / y. \ yXoH    । Q             H fl     H oXX''°H Xy X^^y ■ Ulf Yir v° \yy     o y H o Uy r / \ ^y>         ।              yyieN, \              X             k / / 0Me \             HO O                 J X                                                                ' k IV-E4 Tusamitamab--- / y- \ yy oh     । H ? H n<"0H y<        -^Xy Yir'^o yvy   oyH° MJ y / \ n         y            yyieN, \              X             k / / 0Me \             HO O                           / X                                                                ' k IV-E5 Tusamitamab—- / \ h ? h Dy-"0H k ___        N Jk ni / -^o MX    o y H o uj y / \ n         y            yyieNx \              X             k / / 0Me \             HO O X                                                                ' k IV-E6 Tusamitamab— /        ‘kr \ yy ,oh o           H fl h oyy"OH -yy^^^^yf ^yf 0 r ''^° Jm   o y H o ux y \ n              |                     k^xyieN / \               X              k / / 0Me / \            HO 'O              kk       / '                                                                    ' k IV-E7 Tusamitamab--- t                  \ h ? h r>AoH \Vj     o / H o MJ r / \                 \                r^MeN. \                A               L / / Me \             HO O                           / ' k IV-E8 Tusamitamab—- / A ' h ? h r>voH X ^s.                       J Jx A    f A N Y T 7 V \VJ     o > H o MJ      / \ 0 X      0 \              HO O                            / '                                                           / k IV-E9 < S                 J AN \ H 9 I H ? nA0 NH     / ,- J          I Tusamitamab-^r                   fl        Tl       N R       N             A Y A 0     o /     o = h        rjo 1                          7—f"0H \               0 J               C / T "OH \    ''''O'' ''   '""o"" '"                                      MeN 0             / \                                                     MeO / k IV-E10 9              _  ? A \ nMM h 9 ! h 9 nC0 |H A \ LX J            a / ] a N            H s H H s H          1 H 0 MA _ Tusamitamab^                     A                              — / — \        o nAJ       Ot^oh \                                       MeN^o \                                                      MeO X                                                                                   / k IV-E11 0                \ __ / 0                                J        \^N     \ H 9 ! H ?             NH     J L—'— vnaAx_A a,n A A>,J   A  AS TusamitamabH                     / /        H - N T "A N             Ar, 7 /    / o o > H o = H       L A? rv \          ° J           QAJn \                                             MeN-% \  O's^^o-x\^'O-^^o-x^^'O-^^o-x\ / O\              Meo             / / k IV-E12 n                                0            \ / I                       a     rN \ nAtAa h ? i h ? no a 4   \ 'V / A-v-W AoXj Jr N         o = H o £ H       LI? VO _ Tusamitamatx                        u /       u                               q \                  H                      MeN-% \                                                    MeO / k IV-E13 0) 3 S’ 3 0) CT p \ H I A ° / < ° ? / °¾ °A • ■ ■ O        IZ ? =A O         ZI '      .....Vo IZ -o QaaV \_ / o      z—1 \ IV-E14 OTA / 0 - ZI A..... IZ Ao -V — / ° °T <A“ / =0 0 0 d A TO E eg E cu co IV-E15 C^vL? aDa° 5 A> o^AJ 0s - 0 ZI °v       , IZ         O A° ? ZI        O Am5 $ 12 x—) 0 oj° A A ? \ / ° \ 0 TO E TO E TO co □ IV-E16 A                    A    0rN \ N^lf        H 9 ! H 9 HP0 A A \ P^j ^oANA^yrW 60XJ TusamitamabA                    U A       U                           Aqi । \                 0 nA^°A                       ''oh \                     H      11               W j: \                                          MeN^0 \                                                    MeO X                                                                                     / k IV-E17 DB1001— rj3             A ON \ / ~l     H 9 1 H 9 / A / A NH J A—          X A ° o > H A h     / 19 W r                                / t“oh       1 \         0 j         CrA / k IV-E18 DBWOr I                         ., / / °yN \ N<AA H 9 I H 9 AO0    A \ T      o H o "    UOv 1                        OO-OFT l           o JA          ^A / r "'oh \                                       MeN"% \                                                     MeO '                                                                                         / k IV-E19 DB1OO1- / / / / A           \ O——COOAa XO° a a o    o > H = h       r l°AXn, /             ^ / r"0H \               jH            Or "oh \ |^'o-^ / O / ^'o'^^°'A                    MeAo        / \ O / ^'o^^°'^*'O^ / O'^^'O'^ / °',            MeO / k IV-E20 DBWOr 9                        2 nQ \ nOO H 9 I h 9 A0 iH A \ AJ O^nAnAnAna / A n A      o H 0 H   UOv 1                           OO-OFT \                                       MeN"% \                                                        MeO               / / k IV-E21 DB1OO1" r~^                  / / / / A     °'A'    \ ^-- / 1    H 9 I H 9 rA°^NH J ——OanAVaa A O o o j H A H     / ^900 j                  ^ / A2-ohu \             °"o            Pt^-oh \ \ p / r^^oj         \A       / \                                                                             / k IV-E22 /  ।           ^a rN \ nAA h 9 I H 9 nC0 iH A \ AJ             A / A N          A = H A = H        L 19 A DBWOr                         A"       u                     '''^-...Z-QH0'"" I          0 nYY        A^ / ^'OH \                            H        11                    Xa^                    / '                                                                                                         ' k IV-E23 /            xP                      ?     An \ / ——CXa A Ar A XT"0 x A DB1OO1-9--             if     if Y^^ff                       J! / 0 o > o = H       L A rN \          ° j          nA"™ \                                               MeN"Y         / 9                                                                         / k IV-E24 a                     °r \ nAA h 9 I H 9 AA° ih A \ oVa\ana A A Y N         n ; h n ; h       l YVn DBioor               u X     u              - / VZ-gn I           o^N'A°k         A / r "oh \                                 MeNY \                                                        MeO               / / k IV-E25 .. . s A \ h 9 । h 9 Yr 0 L———— VNsaa / NxAYi'l AJ   X / Y DB1002A-- II        n ; N n       N                     A J        o OA H 0 = H     CL? Av 1                        / —r0H \       0 j       AA \ po^'^'O'^0'^              MeVo \                                                                      / k IV-E26 / a         ^V °r \ nAv h 9 1 H 9 AA° ih A \ A-^ Ayn^nAnAA A / j N                II £ H II i H             1   19 y=f DB1002                  u        u                Y- XcH0"" \            o NY°k          FA^r "oh \                                       H           11                                                              / \                                 MeNY \                                                        MeO               / / k IV-E27 DB1002- o             \ _A                    A     AN   \ h 9 1 H 9 rr° nh —     ATA NY      A A 1 0    0 a 0 £ H      11, nn- \               0 J                Or "'OH \  ^o'^'O'- / xO'^-°'-Y                    MeN-% \ OsY^^qYT'YvYA      MeO / k IV-E28 DB1002' 9                   2 Q \ 1^3 h 9 I h 9 OO° IH A \ OV OvAWA A J] O      0 h 0 h uoyv \                   0 n|Aa0^                          '"OH       / \                                       MeN^0 \                                                     MeO X                                                                            / k IV-E29 DB1002- 4 I $) "A ? LJ ° O        IZ ? «A O         ZI '    .....A IZ - 0 QfyO <1^ \ IV-E30 DB1002' \ i—z 0 oyA? 0=00 0 ' b ZI A..... IZ Ao 0 O A- IV-E31 DB1002- /           z.0                      ?     0   \ —-- / 1    H 9 1 H ? / Y"° NH J ___VnxY^n.xA A ,n,A AJ    X ---     ATA n y           11 ) 0    0 y 0 j H       1A9 Tn \          0 j          OA"™ \ OA^oz\z°\ / VX / O^^              MeO         / / k IV-E32 IV-E33 IV-E34 IV-E35 IV-E36 V-E5 Tusamitamab^ /                             \   HQ        \ n " 5 fNPPhX \°          h 0 h          i;n \                                                                              / k V-E6 / 1 Me \ n APAxP Tusamitamab l     o                H 0   ■ H < |"       °K. Xx \                 0   - H 0                    CN        / \                                                               / k V-E7 Tusamitamab' /    hn /    VX-VA 0      oXyo xYU>A pN             hN--X'V ^^^    PA PAAo       Vn   O \                                     OMe     / '                                                                                   / k V-E8 /                                  -VMe \ / PPX ] Me     \ 1                                   H 9 1 H 9 XJ     h \=n     \ \ T                          ° " H                      CN \                     CT'NH \ / '                                                                                                         / k V-E9 /                 >                 HO O     \ H / NX /                     ,XnH o                1 Me \ °'     0 ° M XXatPi 1 JXN.             '' hn---^n     ^ DB100lX \X^o                      X? \                             CN     / V-E10 /                      >°vk°lN-°Me\ rXX 1 Me \ L^° i 1" / DB1001^yN.^                   () \°          H S ; H         ^<N / V-E17 DB1002' /       hnV o        JuWl Vn      hW^ HA     Vn O \                            GN    / V-E18 DB1002^ 1 Me \ i i" s xaDO \°         H S H         bN \                                                                                     / k V-E19 DB1002' /        HnV       XHK,^N'OMe\ > A 0 0 Abo Abo          O  j \                             CN A V-E20 DB1002^ zA / o X° IZ ZI .....A IZ b O^\^ / j—'-, z / =\ / / ® 3 ® V-E21 DB1002^ zX / o x° IZ OA^' ZI .....A IZ b Hs° JW'5 z / o V-E22 DB 1002,,^ 4’ o=\ ZI .....A IZ ZI & § X-X r° VJ^ b V-E23 DB1002" /        hn-Z       >oAA'OM,i\ L =A»A° mAn An         hn^n^^o L kA HAo      Vn O \                                    OMe     / '                                                                                    / k V-E24 DB1OO2-4-- ■: : U A ° / < ° ? ° °\ °A o ( y—< zi A o         iz ?   «X O          ZI ...... / IZ o A IZ 6 J#* o-AA )—-. z     / —\ W® b CD V-E25 DB1003-J f\^0 AZ o ? o o IZv         1 t A IZ O" / U-o pR o <A ZI b A / Ax5 O-AA )—■-o      / = /   / (J i \           '--- CD           , W V-E26 DB1003. । X   HQ       \ HN—>                        lHOK / Y '^NMe2 \ 0, z__ /    \                                                                \ \ X° =- / NH ° o^N^o      °Y^^°YX^ \ A              / \ Anh          W \ o                     / _V °                      OMe /                                                                           / k V-E27 DB10033 x H°      \ A n M e2 \ °               h ?      h ?      h t\                       n                n                n                               / /   \\ 4                                \ > / N                   N n       N M.o     0   H 0 Yq 0              Ue / /                                                                          / k V-E28 DB1003x /                                   x ^NZ     \ o wA_         ^><h \ kuA1 Anh o         Hl V'V^i \ / ? =A o oz           / oX^oVjf J I               \ hn4 ^o^Vn    0 \ A             / A Anh \ o                      v / ®                       OMe / \                                                                        / k wherein k is as described in any one of the embodiments of the present disclosure. A second aspect of the present disclosure provides a mixture of ligand-drug conjugates, comprising or consisting of the aforementioned ligand-drug conjugate, the tautomer thereof, the enantiomer thereof, the diastereoisomer thereof, the pharmaceutically acceptable salt thereof, or the solvate thereof, wherein the ligand-drug conjugate has one, two, or more k values. In some embodiments, the mixture of ligand-drug conjugates has an average drug-to-ligand ratio (DAR) selected from integers or decimals from 1 to 32. In certain embodiments, the DAR value is selected from integers or decimals from 1 to 16. In certain embodiments, the DAR value is selected from integers or decimals from 2 to 9, preferably integers or decimals from 2 to 8, e.g., 2, 3, 4, 5, 6, 7, 8, 3.01, 3.22, 3.75, 3.76, 3.87, 3.89, 3.95, 3.98, 4.05, 4.06, 4.08, 4.11, 4.16, 4.22, 4.29, 5.11, 5.58, 6.17, 6.46, 6.56, 6.82, 6.88, 6.98, 7.02, 7.06, 7.08, 7.12, 7.18, 7.22, 7.25, 7.28, 7.31, 7.32, 7.33, 7.41, 7.42, 7.43, 7.45, 7.48, 7.52, 7.53, 7.56, 7.57, 7.58, 7.62, 7.64, 7.65, 7.71, 7.73, 7.78, 7.81, 7.82, 7.87, 7.88, or 7.93, e.g., 7.83, 7.84, 7.85, 7.86, 7.89, 7.90, 7.91, 7.92, 7.94, 7.95, 7.96, 7.97, 7.98, 7.99, 8.00, 8.01, 8.02, 8.03, 8.04, 8.05, 8.06, 8.07, 8.08, 8.09, or 8.10. Drug-Linker A third aspect of the present disclosure provides a compound or a racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or a mixture thereof, or a pharmaceutically acceptable salt or solvate thereof, wherein the compound is selected from a structure represented by formula I-D, II-D', III-D', IV-D, or V-D: I-D                                        II-D' III-D'                        IV-D V-D wherein: X, X1, X2, ring A, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, R12, m, n, M, W, U, Z, Y, L, Q, T, Tr, L2, and L3 are defined as described in any one of the embodiments of the first aspect 10 of the present disclosure; L1a is a linking unit. The third aspect of the present disclosure further provides a compound or a racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or a mixture thereof, or a pharmaceutically acceptable salt or solvate thereof, wherein the compound is selected from a 15 structure represented by formula I-D, II-D, III-D, IV-D, or V-D: I-D                                      II-D III-D                       IV-D V-D 5 wherein: X, X1, X2, ring A, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, R12, m, M, W, U, Z, Y, Q, T, Tr, L2, and L3 are defined as described in any one of the embodiments of the first aspect of the present disclosure; L1a is a linking unit. 10 In certain embodiments, the compound is selected from a structure represented by formula I-D: I-D wherein X, X1, X2, ring B, ring C, R3, R4, R5, R6, R8a, R8b, R9a, R9b, R10, M, Tr, L1a, L2, and L3 are 15 defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the compound is selected from a structure represented by formula II-D': II-D' wherein X, X1, X2, ring B, ring C, R3, R4, R5, R6, R7, m, n, W, U, Z, Y, Tr, L1a, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the compound is selected from a structure represented by formula II-D: II-D wherein X, X1, X2, ring B, ring C, R3, R4, R5, R6, R7, m, W, U, Z, Y, Tr, L1a, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the compound is selected from a structure represented by formula III-D': III-D' wherein X, X1, X2, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R12, L, m, Tr, L1a, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the compound is selected from a structure represented by formula III-D: III-D wherein X, X1, X2, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R12, m, Tr, L1a, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the compound is selected from a structure represented by formula IV-D: IV-D wherein X, X1, X2, ring B, ring C, R3, R4, R7, R8a, R8b, R9a, R9b, R10, m, Q, Tr, L1a, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the compound is selected from a structure represented by formula V-D: V-D wherein X, X1, X2, ring A, ring B, ring C, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, m, T, Tr, L1a, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, L1a is selected from -C(=O)-(C1-C8)alkyl, -C(=O)O-(4-8 membered)heterocyclyl, -C(=O)O-(C6-C10)aryl, (4-8 membered)heterocyclyl, and (5-10 membered)heteroaryl, wherein the -C(=O)-(C1-C8)alkyl, -C(=O)O-(4-8 membered)heterocyclyl, -C(=O)O-(C6-C10 membered)aryl, (4-8 membered)heterocyclyl, and (5-10 membered)heteroaryl are optionally substituted with 1, 2, 3, 4, or 5 oxo, halogen, =CH2, -(C2-C4)alkenyl, -S-CH2-phenyl, -S(=O)2-(C1-C4)alkyl, -O-S(=O)2-phenyl-(C1-C4)alkyl, and -(C1-C4)alkyl groups. In certain embodiments, L1a is selected from -C(=O)-(C1-C4)alkyl, -C(=O)O-(5-6 membered)heterocyclyl, -C(=O)O-phenyl, (5-6 membered)heterocyclyl, and (5-6 membered)heteroaryl, wherein the -C(=O)-(C1-C4)alkyl, -C(=O)O-(5-6 membered)heterocyclyl, -C(=O)O-phenyl, (5-6 membered)heterocyclyl, and (5-6 membered)heteroaryl are optionally substituted with 1, 2, 3, 4, or 5 oxo, fluorine, bromine, =CH2, vinyl, -S-CH2-phenyl, -S(=O)2CH3, -O-S(=O)2-phenyl-CH3, and methyl groups. In certain embodiments, L1a is selected from 0 S O , O S z 5 10 , O In certain embodiments, L1a is selected from In certain embodiments, L1a is selected from In certain embodiments, L1a is selected from In certain embodiments, L1a-L2- is selected from 0 . , O=S=O , O N v and O O OO / 'O  O , , , , In certain embodiments, L1a-L2- is selected from 0 In certain embodiments, L1a-L2- is selected from and and In certain embodiments, L1a-L2- is selected from In certain embodiments, L1a-L2- is selected from and O In certain embodiments, L1a-L2- is selected from In certain embodiments, L1a-L2-L3-  is selected from and O O H Nr HN H2N^O H N H O O O H N N H O O O H N 5 H2N h2n and In certain embodiments, L1a-L2-L3- is selected from and 0 In certain embodiments, L1a-L2-L3- is selected from HO^O Y            o. o     - 9         lY        : AH          °    Z H o         °                        o , 0 XAV^A YY X^ Y H    0     o     J H , 0      0                 o H 0 . 5 In certain embodiments, L1a-L2-L3- is selected from „    ooo = 9 H               JI      . 1      Y YY x o A    h o                        0     , and In certain embodiments, L1a-L2-L3-Tr- is selected from 1 HOV / n                    0             H°" 0 H A 0             , £ U     , and 9 h        _ J H J °     o^7 HO^O , AvY , Vv—A °                   d u      , and 0 H             f rN\Nr^^rt i H 1 0          cf , 0 0 . H i 0        / -7 , OH Y^COOH ,° O 0      0                 O N N Y^\o / '\^ A H H          jJ O . In certain embodiments, L1a-L2-L3- H aav E 0 H A 0      0 Z Z A A^n. a A A ZX N Y Y N   nA 5 h i S h 0 , Qx.^ 0 M  A WT (Toh , 9 H          . J? YT^A o H J 0     dH HO^O                , ( IAVa^ V     n h 1 o        o 5            0 9                H 9 I H M,     & A H S ° \ cAnH ^''0 , A H A A A TnY^AA A  P 0,^ o '_A - A / -- /     0 0 H / .Z ^ AY Hlx is selected from H2N 0                        , H VT^y0 e 0      X O              9 / / X JL / n\Y- A^o^^ r"T"SX) X N i n n    V\ H A ° o H I o H    AnAAn 0 , TAky^T J h 1 S / -7 , HO^O Y           o.x^ o        9        Y^% Ai^n^^ T h        o J H      0 H              0 1                                                                                                                                                                                                                                                    , 3 , 0 ^0¾ h           a W......Y9 ,                                                                                                                                      , A H   ^A Ty T^a 0^0 H ,                                                                                                                                                               , OH 0 , and In certain embodiments, L1a-L2-L3- is selected from 5 and In certain embodiments, L1a-L2-L3- is selected from and - is selected from O                         O and In certain embodiments, L1a-L2-L3 0 In certain embodiments, the compound is selected from a structure represented by formula I-D-3, III-D-3', III-D-3, IV-D-3, or V-D-3: 10 R12  ,3 xL1a ' L -i 2 IV-D-3 V-D-3 III-D-3' wherein X, X1, X2, ring A, R3, R4, R5, R6, R7, R8b, R9b, R12, m, M, L, Q, T, Tr, L1a, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the compound is selected from a structure represented by formula I-D-4, 10 II-D-4', II-D-4, III-D-4', III-D-4, IV-D-4, or V-D-4: I-D-4                                     II-D-4 III-D-4                      IV-D-4 15 wherein X, R1, ring A, R3, R4, R5, R6, R7, R8b, R12, m, n, M, W, U, Z, Y, Q, T, Tr, L, L1a, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the compound is selected from a structure represented by formula I-D-5, II-D-5, III-D-5, IV-D-5, or V-D-5: I-D-5 II-D-5 V-D-5 10 wherein X, R1, ring A, R3, R5, R6, R7, R8b, R9a, R9b, R12, n, M, W, U, Z, Y, Q, T, Tr, L, L1a, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the compound is selected from structures represented by formulas I-D-6 and I-D-7: wherein R1, R31, R5, R6, R8b, R9a, R9b, M, Tr, L, L1a, L2, and L3 are defined as described in any one of the embodiments of the present disclosure. In certain embodiments, the compound is selected from the structures shown in Table D: Table D No. Structure I-D1 HO O AAXzAnAnY^^'!? AvVajJ J h I J,    oy~J a wz CN I-D2 NC ° / ¼ N'"Ynz     H 9 I H 9     Ak     n o A J        -V"A A1 Ao^ / A °' \         o y H o H Ne Wk J (       MeO' YAAA O^NH              O OH 0 Zo / zO / o"' ^0^ I-D3 °aa zA xz \--u    O cA '—\ A S a xz Q <D YA ZS ( /   7 °A / A-x Z g" 'yy y5 y° z y I-D4 no^Y0 HO o               Y            o. Oun ' Y zOMe    n   Y0       lA JhoxAtW, h     ? h 7 !l zz / XzNV WrX 1 Me H                    Y H [ VAV Y N   Y H        0 n^yW^oWa J o h 0 A° CN I-D5 wn O                  H ?   9 H               9 ^o za»-“'   rzN'ir'NYNY-^z~.Y (                                     O        * O / NzY^       J o A°     A / ^ CN I-D11 I-D12 0A w 8 / =\ 5=0 Y / / ® \     (D ZI . A o \_Vo o'      \ ZI O, / I-D13 V 2 o4 by Xr-" )--- "Z r ( VJ ZI . °i o zz \_Vo o ''”\ ZI Ox / Yz I-D14 NC °              A nVn-7    H 9 1 H 9 TT LA    n 9' A XXA'UA L 1 1 O^x 7 A o n - N         n 'Xxj / >^\^sx / > o         O A H 0 = H Me TAJ JpN r                Me" A' - ohi O^NH              0 OH °x I-D15 NC 9              X N^XN^\    H 9 1 H 9 AT L J     n °' A ) Xv-^nAnAkAI VVx / J x         o a h s = h cyv' N J                                 : oh / O^NH                 OH °\ I-D16 NC 0 9       h ? I h ? AXo^nAA VV\ JJ Q     <>   " 0   "      MeaNYS\X 1                                    0 OH °\ O^NH I-D17 NC / 0                       0 XT ( J X H 9 1 H ? rV^oAAA    X r^-rW^A "nw " 0    o 0 H 0 = H       MeO yMohY J                                    0 OH 0 0^-NH Ox / oz- --O --' o'- zG^.- oz-x I-D18 NC ||                                                   0 (fjj ojj Na      i 0 H " HUf '           H Me VW J N b            0 > M 0  = H         Me0'"y V bn; f                                    0 OH 0 O' NH x''cy'' x°x''^^ Ox''o'' x°.^ I-D19 z oa Oa Ay z xa j_ / / ^X o A0 WSZx \        <D ZZ 2 °=< $ ZI X     , IZ         o ^>=O ZI        o °=< „    X    < °\ O O 2 b° < o    > O z \ ° / / \ \ ° O ( Q I-D20 NC / 0                                     0         fi J h ? 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IZ         o ^>=o ZT        O °=< H    X    < O O 2 o )          p r z        ° \ / / ° o ° o ( Q I-D28 z O-^ kXo / -o¥>°« Z \z=V \__ / o ZI o=( o $ ZI °i.....      , IZ         O ^>=o ZI        O O=< „    X    < )=o o o 2 d c f °K p p I-D29 p o ) ? ° o ( / \ \ o       z-X ° \        S ° / o o ° >   1 >o O        IZ ?       o=^~" o         zz '        / o IZ o 2 V=O f IZ o \__ O=(^O obL / ° V / bp I-D35 CN I-D40 I-D41 I-D42 H9                                  O HOsA ' N      z 9 H            U J H 1 o Vo CN I-D43 HQ                                 0 ?HO. z.            z 9 H               JI n^J^AoOLJ   H 1 o    0^ vi Q CN I-D44 \ HQ                                0 Yo. / ^z        z 9 H           JI N^dDu I H 1 0   o^ m Q OMe I-D45 ,HQ                   0 ?JUo€TI I H 1 0   0^ M Q OMe I-D46 NMe2 ?HO 5a          z o h             ? rSyVvVA”^—'x5 “yV-oAJJ 1 H 1 i    o^ Vo OMe I-D47 ^?H0. V          z 0 H             9 n^JLAajlJ H 1 o o^ V° OMe III-D1 0 n^nh o 0       -- Vn         0    ' NH 0                     ' ^0H v° OMe III-D2 CD °\       o^ rcxy M<p ° o^ A IZ >° o V oK’Vo @ o \ p z III-D3 H : 9 H                 9 0<^0^U^ 0 H i 0 7                           o NH / ^^<1 ^°H v° OMe III-D4 H H = 9 H ? 9        P O H      o H 7                             o NH 5p0a'''^oh V° OMe III-D13 IV-D1 IV-D2 IV-D3 IV-D4 IV-D10 IV-D11 IV-D12 m                                  O A             yy A   YN n nAn-a    h 9 i h 9 AC0 iH  A Q A I yA   ,n A A ,n A A    A  A A AAa         h T h     Al oA Y  ° oa-'-0!,,            [ / A'-.oh H     11             A = MeN o MeO IV-D13 JO                  A    An AT h 9 I h 9 TT° TH J A- n ,-^          A A>, J A A F A A N A — n Y   A Ji 1 0   o a H o = H     Qaa- r                       —hohu ryv-oH Yo^A °Y0-' ,'0Y"-^ IV-D14 °7y / oaa o ZI A..... iz >o ^3= — /   o <A“ o d A \ xO x<Z) O" \ IV-D15 o y o o ( / \   °y7 ) O        z-A O \       S O ? PA <° Va.A1 >   1    >o O        zz O         ZI '     A IZ - _      o J 2*0 (Az^° O-^ \ \A1 O V-AA^ IV-D16 A            A A n^At-ny     h 9 ! h 9 9ir ° A <A os l H v-A       A A^ ,n, A A A     J / / A A N                II £ H II £ H                 II o yN O             O a      O -             A AXJ / <                        y- / -OH o Nf'-'^l^                          'OH MeN AQ MeO IV-D17 An \ IJ ° / yy° AA\ oh o          h ? I h rXAOH A / \ / \ / xA-AiANxAaA J (TA B o XX / r0 o                  YMeN u                                  /        Me IV-D20 V-D2 V-D3 A fourth aspect of the present disclosure provides use of the compound or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the 5 pharmaceutically acceptable salt or solvate thereof according to any one of the embodiments of the third aspect of the present disclosure in the manufacture of the ligand-drug conjugate according to any one of the embodiments of the first aspect of the present disclosure. Pharmaceutical Composition 10 A fifth aspect of the present disclosure provides a pharmaceutical composition comprising at least one of the ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of the embodiments of the first aspect of the present disclosure, or at least one of the compound or the racemic mixture, tautomer, stereoisomer, enantiomer, or 15 diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of the embodiments of the third aspect of the present disclosure, and one or more pharmaceutically acceptable carriers and / or excipients. A sixth aspect of the present disclosure provides a pharmaceutical composition comprising at least one of the mixture of ligand-drug conjugates according to any one of the embodiments of the second aspect of the present disclosure, and one or more pharmaceutically acceptable carriers and / or excipients. Use A seventh aspect of the present disclosure provides use of the ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of the embodiments of the first aspect of the present disclosure, or the compound or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof or the mixture thereof according to any one of the embodiments of the third aspect of the present disclosure, or the pharmaceutical composition according to any one of the embodiments of the fifth aspect of the present disclosure in the manufacture of a medicament for treating and / or preventing a disease or disorder or reducing the severity of the disease or disorder, wherein the disease or disorder is a tumor or cancer. The seventh aspect of the present disclosure further provides use of the mixture of ligand-drug conjugates according to any one of the embodiments of the second aspect of the present disclosure, or the pharmaceutical composition according to any one of the embodiments of the sixth aspect of the present disclosure in the manufacture of a medicament for treating and / or preventing a disease or disorder or reducing the severity of the disease or disorder, wherein the disease or disorder is a tumor or cancer. The seventh aspect of the present disclosure further provides the ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of the embodiments of the first aspect of the present disclosure, or the compound or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof or the mixture thereof according to any one of the embodiments of the third aspect of the present disclosure, or the pharmaceutical composition according to any one of the embodiments of the fifth aspect of the present disclosure for use in treating and / or preventing a disease or disorder or reducing the severity of the disease or disorder, wherein the disease or disorder is a tumor or cancer. The seventh aspect of the present disclosure further provides the mixture of ligand-drug conjugates according to any one of the embodiments of the second aspect of the present disclosure, or the pharmaceutical composition according to any one of the embodiments of the sixth aspect of the present disclosure for use in treating and / or preventing a disease or disorder or reducing the severity of the disease or disorder, wherein the disease or disorder is a tumor or cancer. The seventh aspect of the present disclosure further provides a method for treating and / or preventing a disease or disorder or reducing the severity of the disease or disorder, comprising administering to an individual in need thereof an effective amount of the ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of the embodiments of the first aspect of the present disclosure, or the compound or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof or the mixture thereof according to any one of the embodiments of the third aspect of the present disclosure, or the pharmaceutical composition according to any one of the embodiments of the fifth aspect of the present disclosure, wherein the disease or disorder is a tumor or cancer. The seventh aspect of the present disclosure further provides a method for treating and / or preventing a disease or disorder or reducing the severity of the disease or disorder, comprising administering to an individual in need thereof an effective amount of the mixture of ligand-drug conjugates according to any one of the embodiments of the second aspect of the present disclosure, or the pharmaceutical composition according to any one of the embodiments of the sixth aspect of the present disclosure. In certain embodiments, the tumor or cancer is selected from leukemia, malignant lymphoma, multiple myeloma, gastric cancer, colorectal cancer, pancreatic cancer, colon cancer, breast cancer, ovarian cancer, liver cancer, and lung cancer. In certain embodiments, the tumor or cancer is selected from leukemia, malignant lymphoma, multiple myeloma, gastric cancer, colorectal cancer, breast cancer, ovarian cancer, liver cancer, and lung cancer. In certain embodiments, the tumor or cancer is selected from gastric cancer, colorectal cancer, breast cancer, ovarian cancer, and liver cancer. In certain embodiments, the colorectal cancer is selected from colorectal adenocarcinoma and colon cancer. In certain embodiments, the tumor or cancer is selected from leukemia, malignant lymphoma, and multiple myeloma. In certain embodiments, the breast cancer is selected from ductal breast cancer. Sequence Information The amino acid sequence of the heavy chain oftusamitamab EVQLQESGPGLVKPGGSLSLSCAASGFVFSSYDMSWVRQTPERGLEWVAYISSGGGITYA PSTVKGRFTVSRDNAKNTLYLQMNSLTSEDTAVYYCAAHYFGSSGPFAYWGQGTLVTVS SASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSS GLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGG PSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQY NSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSR DELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKS 5 RWQQGNVFSCSVMHEALHNHYTQKSLSLSPG (SEQ ID NO: 1) The amino acid sequence of the light chain oftusamitamab DIQMTQSPASLSASVGDRVTITCRASENIFSYLAWYQQKPGKSPKLLVYNTRTLAEGVPS RFSGSGSGTDFSLTISSLQPEDFATYYCQHHYGTPFTFGSGTKLEIKRTVAAPSVFIFPPSDE QLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLS 10 KADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 2) The sequences of the complementarity-determining regions and variable regions of tusamitamab are shown in the table below. No. Description Sequence 53 HCDR1 SYDMS 54 HCDR2 YISSGGGITYAPSTVKG 55 HCDR3 HYFGSSGPFAY 56 LCDR1 RASENIFSYLA 57 LCDR2 NTRTLAE 58 LCDR3 QHHYGTPFT 59 VL DIQMTQSPASLSASVGDRVTITCRASENIFSYLAWYQQKPGKSPKL LVYNTRTLAEGVPSRFSGSGSGTDFSLTISSLQPEDFATYYCQHHYG TPFTFGSGTKLEIK 60 VH EVQLQESGPGLVKPGGSLSLSCAASGFVFSSYDMSWVRQTPERGL EWVAYISSGGGITYAPSTVKGRFTVSRDNAKNTLYLQMNSLTSEDT AVYYCAAHYFGSSGPFAYWGQGTLVTVSS The CDR sequences in the table above are defined using the Kabat numbering system. Any other CDR sequence determination method well-known in the art can also be used to identify the amino 15 acid residues of the CDRs in the variable regions. The amino acid sequence of the heavy chain of the anti-HER3 antibody DB1001 QVQLQQWGAGLLKPSETLSLTCAVYGGSFSGYYWSWIRQPPGKGLEWIGEINHSGSTNY NPSLKSRVTISVETSKNQFSLKLSSVTAADTAVYYCARDKWTWYFDLWGRGTLVTVSSA 20 STKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGL YSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCDKTHTCPPCPAPELLGGPS VFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREE MTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSR WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 3) The amino acid sequence of the light chain of the anti-HER3 antibody DB1001 DIEMTQSPDSLAVSLGERATINCRSSQSVLYSSSNRNYLAWYQQNPGQPPKLLIYWASTR ESGVPDRFSGSGSGTDFTLTISSLQAEDVAVYYCQQYYSTPRTFGQGTKVEIKRTVAAPSV FIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYS LSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGE (SEQ ID NO: 4) The sequences of the complementarity-determining regions and variable regions of the anti-HER3 antibody DB1001are shown in the table below. No. Description Sequence 7 HCDR1 GYYWS 8 HCDR2 EINHSGSTNYNPSLKS 9 HCDR3 DKWTWYFDL 10 LCDR1 RSSQSVLYSSSNRNYLA 11 LCDR2 WASTRES 12 LCDR3 QQYYSTPRT 13 VL DIEMTQSPDSLAVSLGERATINCRSSQSVLYSSSNRNYLAWYQQNP GQPPKLLIYWASTRESGVPDRFSGSGSGTDFTLTISSLQAEDVAVYY CQQYYSTPRTFGQGTKVEIK 14 VH QVQLQQWGAGLLKPSETLSLTCAVYGGSFSGYYWSWIRQPPGKGL EWIGEINHSGSTNYNPSLKSRVTISVETSKNQFSLKLSSVTAADTAV YYCARDKWTWYFDLWGRGTLVTVSS The CDR sequences in the table above are defined using the Kabat numbering system. Any other CDR sequence determination method well-known in the art can also be used to identify the amino acid residues of the CDRs in the variable regions. The amino acid sequence of the heavy chain of the anti-GPC-3 antibody DB1002 QVQLVQSGAEVKKPGASVKVSCKASGYTFTDYEMHWVRQAPGQGLEWMGALDPKTG DTAYSQKFKGRVTLTADKSTSTAYMELSSLTSEDTAVYYCTRFYSYTYWGQGTLVTVSSA STKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGL YSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPS VFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRD ELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSR 5 WQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 5) The amino acid sequence of the light chain of the anti-GPC-3 antibody DB1002 DVVMTQSPLSLPVTPGEPASISCRSSQSLVHSNRNTYLHWYLQKPGQSPQLLIYKVSNRF SGVPDRFSGSGSGTDFTLKISRVEAEDVGVYYCSQNTHVPPTFGQGTKLEIKRTVAAPSV FIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYS 10 LSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 6) The sequences of the complementarity-determining regions and variable regions of the anti-GPC-3 antibody DB1002are shown in the table below. No. Description Sequence 17 HCDR1 DYEMH 18 HCDR2 ALDPKTGDTAYSQKFKG 19 HCDR3 FYSYTY 20 LCDR1 RSSQSLVHSNRNTYLH 21 LCDR2 KVSNRFS 22 LCDR3 SQNTHVPPT 23 VL DVVMTQSPLSLPVTPGEPASISCRSSQSLVHSNRNTYLHWYLQKPGQSPQLLI YKVSNRFSGVPDRFSGSGSGTDFTLKISRVEAEDVGVYYCSQNTHVPPTFGQ GTKLEIK 24 VH QVQLVQSGAEVKKPGASVKVSCKASGYTFTDYEMHWVRQAPGQGLEWMG ALDPKTGDTAYSQKFKGRVTLTADKSTSTAYMELSSLTSEDTAVYYCTRFYSY TYWGQGTLVTVSS The CDR sequences in the table above are defined using the Kabat numbering system. Any other CDR sequence determination method well-known in the art can also be used to identify the amino 15 acid residues of the CDRs in the variable regions. The amino acid sequence of the heavy chain of the anti-ADAM9antibody DB1003 QVQLQQPGTEVVKPGASVKLSCKASGFTFPLYWMHWVRQRPGRGLEWIGRIIPIFGHTK YNEKFKNKATLTADESSSTAYMELRSLTSDDSAVYYCARGGYYYYPREGFLDYWGQGT 20 SVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFP AVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPA PELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTK PREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKL 5 TVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 25) The amino acid sequence of the light chain of the anti-ADAM9antibody DB1003 DIVMTQSPASLSVSPGERASISCRSSQSVDYSGDSYMNWYQQKPGQSPRLLIYAASDRES GVPDRFSGSGSGTDFTLKISRVEEEDAGTYYCQQSREDPFTFGQGTKVDIKRTVAAPSVFI FPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLS 10 STLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 26) The sequences of the complementarity-determining regions and variable regions of the anti-ADAM9antibody DB1003are shown in the table below. No. Description Sequence 27 HCDR1 LYWMH 28 HCDR2 RIIPIFGHTKYNEKFKN 29 HCDR3 GGYYYYPREGFLDY 30 LCDR1 RSSQSVDYSGDSYMN 31 LCDR2 AASDRES 32 LCDR3 QQSREDPFT 33 VL DIVMTQSPASLSVSPGERASISCRSSQSVDYSGDSYMNWYQQKPGQSPRLLIY AASDRESGVPDRFSGSGSGTDFTLKISRVEEEDAGTYYCQQSREDPFTFGQGT KVDIK 34 VH QVQLQQPGTEVVKPGASVKLSCKASGFTFPLYWMHWVRQRPGRGLEWIGRI IPIFGHTKYNEKFKNKATLTADESSSTAYMELRSLTSDDSAVYYCARGGYYYY PREGFLDYWGQGTSVTVSS The CDR sequences in the table above are defined using the Kabat numbering system. Any other CDR sequence determination method well-known in the art can also be used to identify the amino 15 acid residues of the CDRs in the variable regions. The amino acid sequence of the heavy chain of the anti-BCMAantibody DB1004 (i.e., belantamab) QVQLVQSGAEVKKPGSSVKVSCKASGGTFSNYWMHWVRQAPGQGLEWMGATYRGHS DTYYNQKFKGRVTITADKSTSTAYMELSSLRSEDTAVYYCARGAIYDGYDVLDNWGQG 20 TLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTF PAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCP APELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKT KPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSK LTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 35) The amino acid sequence of the light chain of the anti-BCMAantibody DB1004 (i.e., belantamab) DIQMTQSPSSLSASVGDRVTITCSASQDISNYLNWYQQKPGKAPKLLIYYTSNLHSGVPS RFSGSGSGTDFTLTISSLQPEDFATYYCQQYRKLPWTFGQGTKLEIKRTVAAPSVFIFPPSD EQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTL SKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 36) The sequences of the complementarity-determining regions and variable regions of the anti-BCMAantibody DB1004are shown in the table below. No. Description Sequence 37 HCDR1 NYWMH 38 HCDR2 ATYRGHSDTYYNQKFKG 39 HCDR3 GAIYDGYDVLDN 40 LCDR1 SASQDISNYLN 41 LCDR2 YTSNLHS 42 LCDR3 QQYRKLPWT 43 VL DIQMTQSPSSLSASVGDRVTITCSASQDISNYLNWYQQKPGKAPKL LIYYTSNLHSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQYRK LPWTFGQGTKLEIK 44 VH QVQLVQSGAEVKKPGSSVKVSCKASGGTFSNYWMHWVRQAPGQ GLEWMGATYRGHSDTYYNQKFKGRVTITADKSTSTAYMELSSLRS EDTAVYYCARGAIYDGYDVLDNWGQGTLVTVSS The CDR sequences in the table above are defined using the Kabat numbering system. Any other CDR sequence determination method well-known in the art can also be used to identify the amino acid residues of the CDRs in the variable regions. The amino acid sequence of the heavy chain of the anti-c-met antibody DB1005 EVQLVESGGGLVQPGGSLRLSCAASGFTFTDYYMSWVRQAPGKGLEWLGFIRNKANGY TTEYSASVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCARDNWFAYWGQGTLVTVS SASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSS GLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCDCHCPPCPAPELLGGPS VFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYN STYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREE MTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSR 5 WQQGNVFSCSVMHEALHNHYTQKSLSLSPG (SEQ ID NO: 15) The amino acid sequence of the light chain of the anti-c-met antibody DB1005 DIQMTQSPSSLSASVGDRVTITCKSSQSLLASGNQNNYLAWYQQKPGKAPKMLIIWASTR VSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQSYSRPYTFGQGTKVEIKRTVAAPSVF IFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSL 10 SSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 16) The sequences of the complementarity-determining regions and variable regions of the anti-c-met antibody DB1005are shown in the table below. No. Description Sequence 45 HCDR1 DYYMS 46 HCDR2 FIRNKANGYTTEYSASVKG 47 HCDR3 DNWFAY 48 LCDR1 KSSQSLLASGNQNNYLA 49 LCDR2 WASTRVS 50 LCDR3 QQSYSRPYT 51 VL DIQMTQSPSSLSASVGDRVTITCKSSQSLLASGNQNNYLAWYQQKP GKAPKMLIIWASTRVSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYC QQSYSRPYTFGQGTKVEIK 52 VH EVQLVESGGGLVQPGGSLRLSCAASGFTFTDYYMSWVRQAPGKG LEWLGFIRNKANGYTTEYSASVKGRFTISRDNSKNTLYLQMNSLR AEDTAVYYCARDNWFAYWGQGTLVTVSS The CDR sequences in the table above are defined using the Kabat numbering system. Any other CDR sequence determination method well-known in the art can also be used to identify the amino 15 acid residues of the CDRs in the variable regions. The sequences of short peptides No. Description Sequence 61 Short peptide GGGG 62 Short peptide GGFG 63 Short peptide GGEG 64 Short peptide KAAN 65 Short peptide KAAD 66 Short peptide AAPV 67 Short peptide AAPX Note: X represents norvaline (Nva). Definitions of Terms The various terms and phrases used in the present application have general meanings well known to those skilled in the art. Nevertheless, the present application still intends to provide a more detailed illustration and explanation of these terms and phrases herein. In the event of any discrepancy between the terms and phrases mentioned and their well-known meanings, the meanings expressed in the present disclosure shall prevail. The terms “a” and “an” and “the” and similar referents in the context of describing the present disclosure (especially in the context of the claims) are to be construed to cover both the singular and the plural, unless otherwise indicated in the present application or clearly contradicted by context. When the terms “for example”, “such as”, or variants thereof are used in the present application, these terms will not be considered as limiting terms, and will be interpreted as “including but not limited to” or “not limited to”. When the terms “comprise”, “include”, or variants thereof are used in the present application, the meanings of the terms “consist of” and “consist essentially of” are also provided. As used in the present application, the term “and / or” is to be considered as a specific disclosure of each of the two or more specified features or elements, as well as any combination of the two or more features or elements. Thus, the term “and / or” as used in a phrase, such as “A and / or B” herein, is intended to include “A and B”, “A or B”, “A” (alone), and “B” (alone). As used in the present application, the term “pharmaceutically acceptable salt” refers to a salt of a compound of the present disclosure that is pharmaceutically acceptable and possesses the desired pharmacological activity of the parental compound. Such salts include acid addition salts formed with inorganic or organic acids, or salts formed by replacing acidic protons present on the parental compound with metal ions, or coordination complexes formed with organic bases. As used in the present application, the term “stereoisomer” refers to an isomer formed due to the presence of at least one asymmetric center. In compounds having one or more (e.g., 1, 2, 3, or 4) asymmetric centers, racemic mixtures, single enantiomers, mixtures of diastereoisomers, and separate diastereoisomers may be produced. The term “stereoisomer” includes conformational isomers and configurational isomers, wherein the configurational isomers mainly include cis-trans isomers and optical isomers. The compounds of the present disclosure may be present in stereoisomeric forms and thus encompass all possible stereoisomeric forms and any combination thereof or any mixture thereof, for example, single enantiomers, single diastereoisomers, or mixtures of the above. When a compound of the present disclosure contains an olefin double bond, it includes cis-isomers and trans-isomers, as well as any combination thereof, unless otherwise specified. As used in the present application, the term “tautomer” refers to a functional group isomer resulting from the rapid movement of an atom between two positions in a molecule, such as keto-enol tautomers and imine-enamine tautomers. If tautomers of a compound of the present disclosure exist, the compound may be present in the form of a single tautomer or a mixture of tautomers, preferably in a form in which a relatively stable tautomer predominates. As used in the present application, the term “racemic mixture” encompasses “racemate”, and the term “racemate” refers to an equimolar mixture of an optically active chiral molecule and an enantiomer thereof; the term “enantiomer” refers to one of a pair of molecular entities that are mirror images of each other and are non-superimposable, and a mixture of enantiomers can be separated under, for example, chiral resolution conditions; the term “diastereoisomer” refers to a stereoisomer that is not related to mirror images; diastereoisomers are characterized by some differences in physicochemical properties, and a mixture of diastereoisomers can be separated under, for example, chromatographic or crystallization conditions. As used in the present application, the term “solvate” refers to a substance formed by association of a compound of the present disclosure with a solvent molecule. The solvent may be an organic solvent (e.g., methanol, ethanol, propanol, or acetonitrile). For example, the compounds of the present disclosure may form ethanolates with ethanol. The compounds of the present disclosure may also form hydrates with water. The amount of the solvent may be present in a stoichiometric or non-stoichiometric ratio. Unless otherwise defined, the direction of a divalent group is not limited. For example, for A-L-B, when L is -C(=O)-NH-, A-L-B is A-C(=O)-NH-B and / or A-NH-C(=O)-B. As used in the present application, the term “substituted” means that a hydrogen atom in a group is replaced with a corresponding substituent. For example, when the -CH2- in A-CH2-B is substituted with 1 -NH2, A-CH(NH2)-B is obtained. It will be appreciated that a substituent is only in its possible chemical position. As used in the present application, the term “replaced” means that the group itself is replaced with a corresponding group. For example, when the -CH2- in A-CH2-B is replaced with -NH-, A-NH-B is obtained. As used in the present application, “optionally substituted with” means that the group may be unsubstituted or substituted with a substituent. For example, -(C1-C6)alkyl optionally substituted with halogen means that the -(C1-C6)alkyl may be unsubstituted or substituted with halogen, resulting in haloalkyl. It will be appreciated that when a group consists of multiple moieties, defining that one of the moieties can be substituted means that this moiety in the group can also be substituted. For example, the expression “R is selected from -(C1-C6)alkyl, -O-(C1-C6)alkyl, and -NH(C1-C6)alkyl, wherein the -(C1-C6)alkyl is optionally substituted with halogen” means that the -(C1-C6)alkyl, the (C1-C6)alkyl in the -O-(C1-C6)alkyl, and the (C1-C6)alkyl in the -NH(C1-C6)alkyl are all optionally substituted with halogen. For example, the expression “R is selected from methyl, -O-methyl, -NH-methyl, -S-methyl, -C(=O)-methyl, and -C(=O)NH-methyl, wherein the methyl is optionally substituted with 1 hydroxyl or amino group” means that the methyl, as well as the methyl in the -O-methyl, -NH-methyl, -S-methyl, -C(=O)-methyl, and -C(=O)NH-methyl, are all optionally substituted with 1 hydroxyl or amino group. As used in the present application, the term “halogen” refers to fluorine, chlorine, bromine, or iodine. As used in the present application, the term “alkyl” refers to a linear or branched monovalent saturated hydrocarbyl group. For example, (C1-C6)alkyl means having 1 to 6 carbon atoms, such as 1, 2, 3, 4, 5, or 6 carbon atoms; (C1-C4)alkyl means having 1 to 4 carbon atoms, such as 1, 2, 3, or 4 carbon atoms. Non-limiting examples of alkyl include, but are not limited to, methyl, ethyl, propyl, propyl, butyl, etc. As used in the present application, the term “alkylene” refers to a linear or branched divalent saturated hydrocarbyl group. For example, (C1-C6)alkylene means having 1 to 6 carbon atoms, such as 1, 2, 3, 4, 5, or 6 carbon atoms; (C1-C4)alkylene means having 1 to 4 carbon atoms, such as 1, 2, 3, or 4 carbon atoms. Non-limiting examples of alkylene include, but are not limited to, methylene, ethylene, propylene, butylene, etc. As used in the present application, the term “halo” means that the modified group is substituted with one or more halogens, for example, with 1, 2, 3, 4, 5, or 6 halogens. For example, the expression “(C1-C6)haloalkyl” means that the (C1-C6)alkyl defined above is substituted with one or more halogens; non-limiting examples include, but are not limited to, CF3, CHF2, CF2CF3, or the like. As used in the present application, the term “alkenyl” refers to a linear or branched unsaturated hydrocarbyl group containing at least one double bond. (C2-C6)alkenyl means having 2 to 6 (e.g., 2, 3, 4, 5, or 6) carbon atoms, and includes (C2-C5)alkenyl, (C2-C4)alkenyl, (C2-C3)alkenyl, etc.; non-limiting examples include, but are not limited to, -CH=CH2, -CH=CH-CH=CH2, -CH=C(CH)3-CH3, or the like. As used in the present application, the term “alkynyl” refers to a linear or branched unsaturated hydrocarbyl group containing at least one triple bond. For example, (C2-C6)alkynyl means having 2 to 6 (e.g., 2, 3, 4, 5, or 6) carbon atoms, and includes (C2-C5)alkynyl, (C2-C4)alkynyl, (C2-C3)alkynyl, etc.; non-limiting examples include, but are not limited to, ethynyl, propynyl, or the like. As used in the present application, the term “cycloalkyl” refers to a monovalent saturated hydrocarbon group consisting of carbon atoms. For example, (C3-C6)cycloalkyl means consisting of 3-6 (e.g., 3, 4, 5, or 6) carbon atoms. The cycloalkyl includes monocyclic, bicyclic, or polycyclic systems, and includes spiro, fused, or bridged rings. Non-limiting examples include, but are not limited to, cyclobutyl, cyclopentyl, cyclohexyl, or the like. As used in the present application, the term “cycloalkylene” refers to a divalent saturated hydrocarbon group consisting of carbon atoms. For example, (C3-C6)cycloalkylene means consisting of 3-6 (e.g., 3, 4, 5, or 6) carbon atoms. The cycloalkylene includes monocyclic, bicyclic, or polycyclic systems, and includes spiro, fused, or bridged rings. Non-limiting examples include, but are not limited to, cyclobutylene, cyclopentylene, cyclohexylene, or the like. As used in the present application, the term “heterocyclyl” refers to a saturated or partially unsaturated monovalent cyclic group consisting of ring atoms, wherein 1, 2, 3, or 4 of the ring atoms are heteroatoms, and the rest are carbon atoms; preferably, the heteroatoms are selected from N, O, or S, wherein the nitrogen atom is optionally quaternized, and the nitrogen and sulfur heteroatoms may be optionally oxidized; preferably, the carbon atoms are optionally substituted with =O. For example, (4-10 membered)heterocyclyl means consisting of 4, 5, 6, 7, 8, 9, or 10 ring atoms, and (4-10 membered)heterocyclyl includes (4-9 membered)heterocyclyl, (4-8 membered)heterocyclyl, (4-7 membered)heterocyclyl, (4-6 membered)heterocyclyl, 5-membered heterocyclyl, 6-membered heterocyclyl, etc. The heterocyclyl includes monocyclic, bicyclic, or polycyclic systems, and includes spiro, fused, or bridged rings. Non-limiting examples include, but are not limited to, oxetanyl, azetidinyl, pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl, or the like. As used in the present application, the term “heterocyclylene” refers to a saturated or partially unsaturated divalent cyclic group consisting of ring atoms, wherein 1, 2, 3, or 4 of the ring atoms are heteroatoms, and the rest are carbon atoms; preferably, the heteroatoms are selected from N, O, or S, wherein the nitrogen atom is optionally quaternized, and the nitrogen and sulfur heteroatoms may be optionally oxidized; preferably, the carbon atoms are optionally substituted with =O. For example, (4-10 membered)heterocyclylene means consisting of 4-10 (e.g., 4, 5, 6, 7, 8, 9, or 10) ring atoms, and (4-10 membered)heterocyclylene includes (4-8 membered)heterocyclylene, (4-6 membered)heterocyclylene, 5-membered heterocyclylene, etc. The heterocyclylene includes monocyclic, bicyclic, or polycyclic systems, and includes spiro, fused, or bridged rings. Non-limiting examples include, but are not limited to, oxetanylene, azetidinylene, pyrrolidinylene, piperidinylene, piperazinylene, morpholinylene, or the like. As used in the present application, the term “aryl” refers to an unsaturated carbocyclic group having a conjugated n-electron system. For example, (C6-Cio)aryl consists of 6 to 10 (e.g., 6, 7, 8, 9, or 10) carbon atoms. Non-limiting examples include, but are not limited to, phenyl, etc. As used in the present application, the term “arylene” refers to a divalent unsaturated carbocyclic group having a conjugated n-electron system. For example, (C6-Cio)arylene consists of 6 to 10 (e.g., 6, 7, 8, 9, or 10) carbon atoms. Non-limiting examples include, but are not limited to, phenylene, etc. As used in the present application, the term “heteroaryl” refers to an unsaturated group having a conjugated n-electron system and consisting of ring atoms, wherein 1, 2, 3, or 4 of the ring atoms are heteroatoms, and the rest are carbon atoms; preferably, the heteroatoms are selected from N, O, or S, wherein the nitrogen atom is optionally quaternized, and the nitrogen and sulfur heteroatoms may be optionally oxidized. For example, (5-12 membered)heteroaryl consists of 5 to 12 (e.g., 5, 6, 7, 8, 9, 10, 11, or 12) ring atoms, and includes 5-9 membered heteroaryl, 6-9 membered heteroaryl, 5-6 membered heteroaryl, etc. The heteroaryl includes monocyclic and polycyclic systems; non-limiting examples include, but are not limited to, imidazolyl, pyridinyl, or the like. As used in the present application, the term “heteroarylene” refers to an unsaturated group having a conjugated n-electron system and consisting of ring atoms, wherein 1, 2, 3, or 4 of the ring atoms are heteroatoms, and the rest are carbon atoms; preferably, the heteroatoms are selected from N, O, or S, wherein the nitrogen atom is optionally quaternized, and the nitrogen and sulfur heteroatoms may be optionally oxidized. For example, (5-10 membered)heteroarylene consists of (5 to 10) (e.g., 5, 6, 7, 8, 9, or 10) ring atoms, and includes 5-9 membered heteroarylene, 6-9 membered heteroarylene, 5-6 membered heteroarylene, etc. The heteroarylene includes monocyclic and polycyclic systems; non-limiting examples include, but are not limited to, imidazolylene, pyridinylene, or the like. As used in the present application, the abbreviations for amino acids have meanings well-known in the art. The amino acids are generally L-amino acids. Those skilled in the art will appreciate that they may also be replaced with D-amino acids with similar chemical properties. For example, Val represents valine, Ala represents alanine, Glu represents glutamic acid, Cit represents citrulline, Nva represents norvaline, and Lys(AC) represents acetylated lysine. As used in the present application, the term “short peptide” refers to a chain comprising at least two contiguously linked amino acid residues. Unless otherwise stated, the direction in which a short peptide is linked is not limited to the indicated direction. For example, for A-short peptide-B, if the short peptide is Ala-Val, it may be A-Ala-Val-B or A-Val-Ala-B. As used in the present application, the term “linking unit” refers to a fragment for linking an antibody. As used in the present application, the term “about” generally means a variation within 0.5%-10% above or below the stated numerical value, for example, a variation within 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, or 10% above or below the stated numerical value. Unless otherwise apparent from the context, all numerical values provided herein are modified by the term “about”. The endpoints of the ranges and any values disclosed in the present application are not limited to the precise ranges or values, and these ranges or values should be interpreted as including values close to these ranges or values. For numerical ranges, the endpoint values of the ranges, the endpoint values of the ranges and the discrete point values, and the discrete point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in the present application. As used in the present application, the term “antibody” refers to any antibody form having the desired bioactivity. Thus, it is used in the broadest sense and specifically includes, but is not limited to, monoclonal antibodies (including full-length monoclonal antibodies), polyclonal antibodies, multispecific antibodies (e.g., bispecific antibodies), humanized antibodies, fully human antibodies, chimeric antibodies, and camelized single-domain antibodies. As used in the present application, the term “monoclonal antibody” refers to an antibody obtained from a substantially homogeneous population of antibodies, which means that the antibodies comprising the population are identical except for a small number of possible naturally occurring mutations that may be present. A monoclonal antibody is highly specific and targets a single antigen epitope. In contrast, conventional (polyclonal) antibody preparations typically include a large number of antibodies targeting (or specific for) different epitopes. The modifier “monoclonal” indicates the characteristics of an antibody obtained from a substantially homogeneous population of antibodies, and shall not be interpreted as requiring any particular method to produce the antibody. As used in the present application, the term “antigen-binding fragment” of an antibody includes fragments or derivatives of the antibody, generally including at least one fragment of an antigenbinding region or variable region (e.g., one or more CDRs) of the parental antibody that retains at least some of the binding specificity of the parental antibody. Examples of binding fragments of an antibody include, but are not limited to, Fab, Fab', F(ab')2, and Fv fragments; bispecific antibodies; linear antibodies; single-chain antibody molecules, such as scFv; and nanobodies and multispecific antibodies formed from fragments of the antibody. A binding fragment or a derivative generally retains at least 10% of its antigen-binding activity when the antigen-binding activity is expressed on a molar concentration basis. Preferably, the binding fragment or the derivative retains at least 20%, 50%, 70%, 80%, 90%, 95%, or 100% or more of the antigen-binding affinity of the parental antibody. It is also contemplated that an antigen-binding fragment of an antibody may include conservative or non-conservative amino acid substitutions that do not significantly alter its bioactivity (referred to as “conservative variants” or “functionally conservative variants” of the antibody). In the present application, the term “ligand-drug conjugate” generally means that a ligand is linked to a biologically active cytotoxic drug by a stable linking unit. In some embodiments of the present application, the “ligand-drug conjugate” may be an antibody-drug conjugate (ADC). The ADC may mean that a monoclonal antibody or an antigen-binding fragment is linked to a biologically active cytotoxic drug by a stable linking unit. In the present application, the term “ligand” generally refers to small molecules, polypeptides, RNA, DNA, sugars, and macromolecular compounds capable of recognizing and binding to an antigen or receptor associated with a target cell. The role of ligands may be to present the drug to a target cell population to which the ligands bind, and these ligands include, but are not limited to, protein hormones, lectin, growth factors, antibodies, or other molecules capable of binding to cells, receptors, and / or antigens. In the present application, a ligand may be represented as Ab, a ligand antigen forms a linking bond with a linking unit (also referred to as “linker”) through a heteroatom on the ligand, and the ligand may be an antibody or an antigen-binding fragment thereof, wherein the antibody may be selected from a chimeric antibody, a humanized antibody, a fully human antibody, or a murine antibody; the antibody may be a monoclonal antibody; the antibody may be a bispecific antibody. For example, the antibody may be an antibody that targets a target selected from the following targets: HER2, B7H3, TROP2, Claudin 18.2, CD30, CD33, CD70, and EGFR. For example, the antibody may be an antibody that targets a target selected from the following targets: 5T4, AGS-16, ANGPTL4, ApoE, CD19, CTGF, CXCR5, FGF2, MCPT8, MFI2, MS4A7, NCA, Sema5b, SLITRK6, STC2, TGF, 0772P, 5T4, ACTA2, ADGRE1, AG-7, AIF1, AKR1C1, AKR1C2, ASLG659, Axl, B7H3, BAFF-R, BCMA, BMPR1B, BNIP3, C1QA, C1QB, CA6, CADM1, CCD79b, CCL5, CCR5, CCR7, CD1lc, CD123, CD138, CD142, CD147, CD166, CD19, CD19,CD22, CD21, CD20, CD205, CD22, CD223, CD228, CD25, CD30, CD33, CD37, CD38, CD40, CD45, CD45(PTPRC), CD46, CD47, CD49D(ITGA4), CD56, CD66e, CD70, CD71, CD72, CD74, CD79a, CD79b, CD80, CDCP1, CDH11, CDllb, CEA, CEACAM5, c-Met, COL6A3, COL7A1, CRIPTO, CSF1R, CTSD, CTSS, CXCL11, CXCL10, DDIT4, DLL3, DLL4, DR5, E16, EFNA4, EGFR, EGFRvIII, EGLN, EGLN3, EMR2, ENPP3, EpCAM, EphA2, EphB2R, ETBR, FcRH2, FcRHl, FGFR2, FGFR3, FLT3, FOLR-a, GD2, GEDA, GPC-1, GPC-3, GPNMB, GPR20, GZMB, HER2, HLA-DOB, HMOX1, IFI6, IFNG, IGF-1R, IGFBP3, IL10RA1, IL-13R, IL-2, IL20Ra, IL-3, IL-4, IL-6, IRTA2, KISS1R, KRT33A, LIV-1, LOX, LRP-1, LRRC15, LUM, LY64, LY6E, Ly86, LYPD3, MDP, MMP10, MMP14, MMP16, MPF, MSG783, MSLN, MUC-1, NaPi2b, Napi3b, Nectin-4, NOG, P2X5, pCAD, P-Cadherin, PDGFRA, PDK1, PD-L1, PFKFB3, PGF, PGK1, PIK3AP1, PIK3CD, PLOD2, PSCA, PSCAhlg, PSMA, PTK7, P-Cadherin, RNF43, ROR1, ROR2, SERPINE1, SLC39A6, SLTRK6, STAT1, STEAP1, STEAP2, TCF4, TENB2, TGFB1, TGFB2, TGFBR1, TNFRSF21, TNFSF9, Trop-2, TrpM4, Tyro7, UPK1B, VEGFA, WNT5A, ADAM9, epidermal growth factors, brevican, mesothelin, sodium phosphate cotransporter 2B, Claudin18.2, endothelin receptors, mucins (e.g., mucin 1 and mucin 16), guanylate cyclase C, integrin a4p7, integrin avP6, trophoblast glycoprotein, and tissue factors. As used in the present application, the term “specific binding”, “specificity”, or “specific for” refers to a non-random binding reaction between two molecules, such as a reaction between an antibody and an antigen that it targets. In certain embodiments, an antibody that specifically binds to an antigen (or an antibody that is specific for an antigen) means that the antibody binds to the antigen with an affinity (KD) of less than about 10-5 M, e.g., less than about 10-6 M, 10-7 M, 10-8 M, 10-9 M, or 10-10 M or less. The term “drug loading” generally refers to the average number of cytotoxic drugs loaded on each ligand, and may also be represented as the ratio of the number of cytotoxic drugs to the number of ligands, such as average drug / ligand ratio (DAR). The cytotoxic drug loading may be an integer or a decimal ranging from 0 to 20. In the embodiments of the present application, the drug / ligand ratio is represented as k, and may illustratively be an integer or a decimal from 1 to 2, from 2 to 3, from 3 to 4, from 4 to 5, from 5 to 6, from 6 to 7, from 7 to 8, from 8 to 9, or from 9 to 10. The drug loading of each ADC molecule after a conjugation reaction can be determined by conventional methods such as UV / visible spectroscopy, mass spectrometry, HIC, ELISA, and HPLC characterization. As used in the present application, the term “pharmaceutically acceptable carriers and / or excipients” refers to carriers and / or excipients that are pharmacologically and / or physiologically compatible with the subject and the active ingredient, which are well-known in the art (see, e.g., Remington’s Pharmaceutical Sciences. Edited by Gennaro AR, 19th ed. Pennsylvania: Mack Publishing Company, 1995). Pharmaceutically acceptable carriers and / or excipients include, but are not limited to: pH modulators, surfactants, ionic strength enhancers, diluents, agents for maintaining osmolality, agents for delaying absorption, preservatives, and stabilizers. For example, pH modulators include, but are not limited to, phosphate buffers. Surfactants include, but are not limited to, cationic, anionic, or non-ionic surfactants, such as Tween-80. Ionic strength enhancers include, but are not limited to, sodium chloride. Preservatives include, but are not limited to, various antibacterial agents and antifungal agents, such as parabens, chlorobutanol, phenol, sorbic acid, etc. Agents for maintaining osmolality include, but are not limited to, sugars, NaCl, and analogs thereof. Agents for delaying absorption include, but are not limited to, monostearates and gelatin. Diluents include, but are not limited to, water, aqueous buffers (e.g., buffered saline), alcohols, polyols (e.g., glycerol), etc. Preservatives include, but are not limited to, various antibacterial agents and antifungal agents, such as thimerosal, 2-phenoxyethanol, parabens, chlorobutanol, phenol, sorbic acid, etc. Stabilizers have the meaning generally understood by those skilled in the art, are capable of stabilizing the desired activity of the active ingredient in a drug, and include, but are not limited to, sodium glutamate, gelatin, SPGA, sugars (e.g., sorbitol, mannitol, starch, sucrose, lactose, dextran, or glucose), amino acids (e.g., glutamic acid or glycine), proteins (e.g., dried whey, albumin, or casein) or degradation products thereof (e.g., lactalbumin hydrolysates), etc. As used in the present application, the term “treat”, “treating”, or “treatment” are intended to alleviate, palliate, ameliorate, or eliminate a targeted disease state or disorder. A subject is considered successfully “treated” if there is an observable and / or detectable reduction or improvement in one or more indications and symptoms of the subject after the subject receives a therapeutic amount of the ligand-drug conjugate or a racemic mixture, enantiomer, diastereoisomer, or pharmaceutically acceptable salt thereof, or a mixture of the aforementioned forms, according to the method described herein. It will also be appreciated that the treatment of the disease state or disorder includes not only complete treatment, but also achieving some biologically or medically related outcomes even if complete treatment is not attained. As used in the present application, the term “prevent”, “preventing”, or “prevention” is intended to avoid, reduce, block, or delay the occurrence of a disease or disease-related symptom that has not yet appeared before the administration of a related drug. “Prevention” does not necessarily require completely blocking the onset of a disease or disease-related symptom. For example, if the administration of a related drug can reduce the subject’s risk of developing the specific disease or disease-related symptom, or reduce the severity of a related symptom that appears later, the onset or development of the disease can be considered to be “prevented”. As used in the present application, the DMSO solvent used for dissolving compounds in the identification of structures by nuclear magnetic resonance is deuterated DMSO, i.e., DMSO-d6. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the in vivo inhibitory effects of the ligand-drug conjugates of the present disclosure on HPAF-II graft tumors. FIG. 2 shows the in vivo inhibitory effects of the ligand-drug conjugates of the present disclosure on Panc 08.13 graft tumors. FIG. 3 shows the in vivo inhibitory effects of the ligand-drug conjugates of the present disclosure (5 mg / kg) on NCI-H929 graft tumors. FIG. 4 shows the in vivo inhibitory effects of the ligand-drug conjugates of the present disclosure (3 mg / kg) on NCI-H929 graft tumors. FIG. 5 shows the in vivo inhibitory effects of the ligand-drug conjugates of the present disclosure on KMS11 graft tumors. FIG. 6 shows the in vivo inhibitory effects of the ligand-drug conjugates of the present disclosure on SNU-5 graft tumors. FIG. 7 shows the in vivo inhibitory effects of the ligand-drug conjugates of the present disclosure on Calu3 graft tumors. FIG. 8 shows the in vivo inhibitory effects of the ligand-drug conjugates of the present disclosure on NCI-H1975 graft tumors. FIG. 9 shows the in vivo inhibitory effects of the ligand-drug conjugates of the present disclosure on NCI-H820 graft tumors. FIG. 10 shows the in vivo inhibitory effects of the ligand-drug conjugates of the present disclosure on LD1-0038-361928 graft tumors. Beneficial Effects The linker-protein translation inhibitor conjugates provided in the present disclosure have one or more of the following advantages: (1) having extremely high stability; (2) having extremely high conjugation efficiency; and (3) the conjugation reaction being insensitive to pH, and having relatively high conjugation efficiency at a pH value of 4.0-9.0. The ligand-drug conjugates of the present disclosure have one or more of the following advantages: (1) conjugates obtained according to the conjugation mode of the present disclosure being capable of effectively improving the stability of the drug molecule in circulation, thereby reducing the shedding of the drug on non-target cells; and reducing off-target toxicity; (2) the conjugates having good tumor tissue-targeting capability; and (3) the conjugates having good therapeutic effects on animal models of tumors. In addition, the conjugation mode described in the present disclosure has a relatively wide application range, and can be widely used for the conjugation of biologically active molecules to antibodies or targeting small molecule ligands. In summary, the linkers and ligand-drug conjugates of the present disclosure have great clinical value. DETAILED DESCRIPTION The embodiments of the present disclosure are described in detail below with reference to examples. However, those skilled in the art will appreciate that the following examples are only used to illustrate the present disclosure and should not be construed as limiting the scope of the present disclosure. Procedures without specified conditions in the examples were conducted under conventional conditions or conditions recommended by the manufacturers. All reagents or instruments used herein without specified manufacturers were commercially available conventional products. Salts of the compounds obtained in the present disclosure can all be 5 neutralized by conventional methods to give the corresponding free base compounds. Table 1 Abbreviation Meaning Abbreviation Meaning DMF N,N-Dimethylformamide HOBT 1 -Hydroxybenzotriazole DIEA Diisopropylethylamine LC-MS Liquid chromatography-mass spectrometry HPLC High-performance liquid chromatography TLC Thin-layer chromatography HATU O-(7-Azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate Na2SO4 Anhydrous sodium sulfate EA or EtOAc Ethyl acetate DMSO Dimethyl sulfoxide DIPEA N,N- Diisopropylethylamine Pd(dba)3 Tris(dibenzylideneacetone)dipa lladium Boc2O Di-tert-butyl dicarbonate THF Tetrahydrofuran MeCN Acetonitrile NaBH(OAc)3 Sodium triacetoxyborohydride Pd / C Palladium on carbon NaOMe Sodium methoxide CS2CO3 Cesium carbonate Pd(PPh3)4 Tetrakis(triphenylphosphine)pa lladium AcOH Acetic acid Zn(CN)2 Zinc cyanide DPPF 1,1'- Bis(diphenylphosphino)fe rrocene LiOH.H2O Lithium hydroxide monohydrate NMP N-Methyl-2-pyrrolidone Pd(OH)2 / C Palladium hydroxide on carbon STAB Sodium triacetoxyborohydride PPh3 Triphenylphosphine Pd(OAc)2 Palladium acetate Pyridine.HF Pyridine hydrofluoride DIAD Diisopropyl azodicarboxylate FA Formic acid EDCI 1-Ethyl-(3- dimethylaminopropyl)car bodiimide hydrochloride TEA Triethylamine DMA Dimethylamine CHCl3 Trichloromethane, chloroform TFE Trifluoroethanol t-Buxphos Pd G3 Methanesulfonato(2-di-tert-butylphosphino-2',4',6'-triisopropyl-1,1 '-biphenyl)(2'-amino- 1,1'-biphenyl-2-yl)palladium(II) PE Petroleum ether DMAc N,N-Dimethylacetamide TIPS Triisopropylsilyl TMP 2,4,6-Trimethylpyridine HOAT N-Hydroxy-7-azabenzotriazole Na(AcO)3BH Sodium triacetoxyborohydride General chiral column resolution method The racemate compounds of the present disclosure were dissolved in methanol and resolved on a preparative chiral chromatography column (see the table below) to give the product compounds. 5 The absolute configurations of the compounds can be determined by methods such as optical rotation detection and X-ray single-crystal diffraction. Instrument SFC-150 Mgm (Waters) or equivalent instrument Preparative chiral chromatography columns Daicel IC (25 x 250 mm, 10 gm), Daicel OJ (25 x 250 mm, 10 gm), Daicel AD (25 x 250 mm, 10 gm), or chromatography columns of other brands Column temperature 30 °C Mobile phases Mobile phase A: CO2 Mobile phase B: MeOH or EtOH, with 0.2-0.5% NH3 (7 M in MeOH) added Flow rate 100 ml / min Detection wavelength 214 nm Example 1: Synthesis of Intermediates Example 1.1: Synthesis of Small Molecule Compounds Compounds 1 and 1A Compounds 1 and 1A were synthesized according to Liu, Tao; Nair, Somarajan J.; Lescarbeau, Andre; Belani, Jitendra; Peluso, Stephane; Conley, James et al. (2012): Synthetic silvestrol analogues as potent and selective protein synthesis inhibitors. In Journal of medicinal chemistry 55 (20), pp. 8859-8878. DOI: 10.1021 / jm3011542. See compound S2 on page 7 of Supporting 10 Information. Compound 2 15 Step 1: Aftercompound1 (750 mg, 1.66 mmol) and compound 2A (2752 mg, 9.93 mmol) were dissolved in CHCl3 / TFE (7 / 3, 15 mL), a 20 mL syringe was used to inject the reaction mixture at a rate of 15 mL / h through a syringe pump into a coil wound around a jacketed glass cylinder equipped with a 250 W ultraviolet lamp. The temperature of the external circulation cold trap was adjusted to keep the internal reaction temperature at 0-5 °C, and the UV lamp was turned on simultaneously. The reaction mixture was irradiated for 1 h, concentrated under reduced pressure to remove the solvent, and then separated by column chromatography (EA / PE = 1 / 3) to remove the excess cinnamate, giving a racemate of the desired product 2B (crude, 900 mg, yield: 75%) as a yellow oil. LCMS [M+H+18]+ = 748.5. Step 2: The racemate of compound 2B (5.2 g, 7.96 mmol) was mixed with MeOH (50 mL), and NaOMe (1.1 g, 19.91 mmol) was added at 0 °C. The mixture was stirred at 65 °C for 1.5 h. The solution was concentrated, sequentially washed with H2O, an aqueous NH4Cl solution, and saturated brine, dried over Na2SO4, concentrated under reduced pressure, and purified by silica gel column chromatography (0.2% FA, EA / PE = 1 / 3) to give a racemate of compound 2C (3.8 g, yield: 65%). LCMS [M+H-18]+ = 714.4. Step 3: The racemate of compound 2C (3.8 g, 5.21 mmol) was mixed with MeCN / CHCl3 (1 / 1, 100 mL / 100 mL), and NaBH(OAc)3 (5.5 g, 26.03 mmol) and AcOH (3.1 g, 52.05 mmol) were added at 0 °C. The mixture was stirred at room temperature for 2 h. The reaction solution was extracted with EA. The organic phase was sequentially washed with water and saturated brine, dried over anhydrous Na2SO4, and purified by silica gel column chromatography (PE:EA = 1 / 1) to give a racemate of compound 2D (1.9 g, yield: 50%). LCMS [M+H]+ = 716.5. Step 4: A solution of the racemate of compound 2D (1.3 g, 1.78 mmol), Pd2(dba)3 (325.0 mg, 0.36 mmol), DPPF (393.6 mg, 0.71 mmol), and Zn(CN)2 (519.5 mg, 4.44 mmol) in NMP (20 mL) was heated to 150 °C and heated at this temperature for 2 h. The solution was diluted with water, extracted with EA, sequentially washed with water and brine, dried over anhydrous Na2SO4, and purified by silica gel column chromatography (EA / PE = 1 / 1) to give a racemate of compound 2E (1.1 g, yield: 91%). 1H NMR (400 MHz, CDCI3) 8 7.48-7.40 (m, 6H), 7.37 (dt, J = 12.4, 5.3 Hz, 3H), 6.96 (t, J = 7.9 Hz, 1H), 6.85 (s, 1H), 6.51 (d, J = 7.7 Hz, 1H), 6.45 (s, 1H), 6.36 (d, J = 1.9 Hz, 1H), 6.22 (d, J = 1.9 Hz, 1H), 5.09 (d, J = 1.7 Hz, 2H), 5.01 (d, J = 6.4 Hz, 1H), 4.35 (d, J = 14.2 Hz, 1H), 3.953.81 (m, 4H), 3.66 (d, J = 3.8 Hz, 3H), 1.53-1.47 (m, 9H). LCMS [M+H-18]+ = 605.4. Step 5: Pd(OH)2 / C (10%, 250 mg) was added to a solution of the racemate of compound 2E (500.0 mg, 0.74 mol) in EA / MeOH / THF / DCM (20:2:2:0.2, 40 mL). The mixture was purged with hydrogen three times and stirred at room temperature for 16 h. The suspension was filtered, and the filter cake was washed with MeOH / DCM (1 / 10). The filtrate was concentrated and purified by silica gel column chromatography (DCM / MeOH = 10 / 1) to give a racemate of compound 2F (300 mg, yield: 69%). 1H NMR (400 MHz, CDCl3) 8 7.42 (d, J = 8.6 Hz, 2H), 7.33 (d, J = 8.6 Hz, 2H), 6.98 (dd, J = 16.1, 8.2 Hz, 1H), 6.87 (s, 1H), 6.51 (d, J = 7.7 Hz, 1H), 6.33 (s, 1H), 6.24 (d, J = 1.8 Hz, 1H), 6.12 (d, J = 1.7 Hz, 1H), 4.98 (d, J = 6.3 Hz, 1H), 4.35 (d, J = 14.2 Hz, 1H), 3.90 (dd, J = 14.1, 6.4 Hz, 1H), 3.83 (d, J = 15.4 Hz, 3H), 3.67 (d, J = 4.5 Hz, 3H), 1.50 (d, J = 4.8 Hz, 9H). LCMS [M+H]+ = 515.4. Step 6: The racemate of compound 2F (306.0 mg, 0.52 mmol) and K2CO3 (143.6 mg, 1.04 mmol) were stirred in DMF (10 mL). Compound 2G (185.8 mg, 0.52 mmol) was added. The reaction solution was stirred at 60 °C for 20 min, diluted with water, extracted with EA, sequentially washed with water and brine, dried over anhydrous Na2SO4, and purified by silica gel column chromatography (EA / PE = 1 / 1) to give a racemate of compound 2H (300 mg, yield: 80%). 1H NMR (400 MHz, CDCI3) 8 7.41 (d, J = 8.4 Hz, 2H), 7.33 (d, J = 8.5 Hz, 2H), 7.00-6.92 (m, 2H), 6.69 (d, J = 1.7 Hz, 1H), 6.53 (d, J = 7.6 Hz, 1H), 6.45 (d, J = 1.7 Hz, 1H), 6.39 (s, 1H), 4.99 (d, J = 5.9 Hz, 1H), 4.39 (d, J = 14.2 Hz, 1H), 3.99-3.91 (m, 4H), 3.68 (s, 3H), 1.50 (s, 9H). LCMS [M-H]+ = 719.2. Step 7: A solution of the racemate of compound 2H (30 mg, 0.042 mmol) was added to DMF (3 mL), and compound 2I (60 mg, 0.167 mmol), Pd(PPh3)4 (4.8 mg, 0.0042 mmol), and CuI (1.6 mg, 0.0083 mmol) were added under a nitrogen atmosphere. The mixture was stirred at 100 °C for 1 h. The suspension was filtered and then purified by silica gel column chromatography (DCM / MeOH = 10 / 1) to give a racemate of compound 2J (15 mg, yield: 56%). LCMS [M+H]+ = 640.3. Step 8: THF / 6 M HCl (1 / 1, 4 mL) was added to a solution of the racemate of compound 2J (15 mg, 0.02 mmol), and the mixture was stirred at room temperature for 1 h. The solution was concentrated and purified by silica gel column chromatography (DCM / MeOH) to give a racemate of 2 (4.5 mg, yield: 35%) as a white solid, and the racemate was further resolved on a chiral column to give compound 2. LCMS [M+H]+ = 540.1. 1H NMR (400 MHz, DMSO) 8 8.25 (d, J = 0.7 Hz, 1H), 7.50 (d, J = 8.6 Hz, 2H), 7.41 (d, J = 0.7 Hz, 1H), 7.31 (d, J = 8.6 Hz, 2H), 7.19 (d, J = 1.1 Hz, 1H), 7.14 (d, J = 1.0 Hz, 1H), 6.67 (t, J = 7.7 Hz, 1H), 6.26 (s, 1H), 6.19-6.10 (m, 2H), 5.63 (s, 1H), 5.45 (d, J = 5.4 Hz, 1H), 4.83 (s, 2H), 4.66 (t, J = 5.1 Hz, 1H), 4.27 (d, J = 14.0 Hz, 1H), 3.97 (dd, J = 13.9, 4.8 Hz, 1H), 3.83 (s, 3H), 3.58 (s, 3H). Step 9: 60% NaH(21.87 g, 546.88 mmol)was added to THF (2.5 L) at 0 °C, and the mixture was stirred at 0 °C for 1 h. Subsequently, compound 2L (99.59 g, 546.88 mmol) was added dropwise, and the mixture was stirred at 0 °C for 2 h. A solution of compound 2K (100.00 g, 451.97 mmol) in THF (300 mL) was added dropwise. After the mixture was stirred at room temperature for 3 h, 10% HCl was added, and the mixture was then extracted with ethyl acetate. The organic phases were combined, dried over Na2SO4, filtered, and concentrated to give a crude product, and the crude product was slurried with MTBE to give 2A (120 g, yield: 95.73%) as a pale yellow solid. 1H NMR (400 MHz, DMSO) 8 9.47 (s, 1H), 7.74 (s, 1H), 7.58 (d, J = 16.0 Hz, 1H), 7.49 (d, J = 7.2 Hz, 1H), 7.36-7.28 (m, 2H), 6.49 (d, J = 16.0 Hz, 1H), 3.73 (s, 3H), 1.49 (s, 9H). Compound 3 Step 1: Na2CO3 (48.8 mg, 0.14 mL), Pd(PPh3)4 (4.88 mg, 0.01 mmol), and compound 3A (28.3 mg, 0.08 mmol) were added to a solution of the racemate of compound 2H (50 mg, 0.07 mmol) in dioxane / water (2 mL / 0.5 mL). The mixture was left to react at 80 °C for 2 h under a nitrogen atmosphere, filtered, and concentrated under reduced pressure, and the crude product was purified by flash column chromatography (DCM / EA = 1 / 1) to give a racemate of compound 3B (40 mg, yield: 76%) as a light yellow solid. LCMS: [M+H]+ = 796.4. Step 2: The racemate of compound 3B (20 mg, 0.025 mmol) was dissolved in 6 M HCl (1 mL) / THF (0.5 mL), and the solution was stirred for 3 h. The reaction solution was purified by preparative HPLC (ACN / H2O, from 0 to 100%) to give a racemate of 3 (6 mg, yield: 45%) as a white solid, and the racemate was further resolved on a chiral column to give compound 3. LCMS: [M+H]+ = 540.2. 1H NMR (400 MHz, DMSO) 8 8.46 (s, 1H), 7.79 (s, 1H), 7.51 (d, J = 8.4 Hz, 2H), 7.32 (d, J = 8.4 Hz, 2H), 7.03-6.89 (m, 3H), 6.68 (s, 3H), 4.68 (d, J = 4.8 Hz, 1H), 4.34 (d, J = 13.6 Hz, 1H), 4.09 (dd, J = 14.0, 4.8 Hz, 1H), 3.83 (s, 3H), 3.59 (s, 3H). Compound 4 Step 1: A solution of the racemate of compound 2J (150 mg, 0.23 mmol) and LiOH (25 mg, 0.59 mmol) in THF / H2O / MeOH (10 mL) was stirred at room temperature for 3 h. The pH was adjusted to 5 with 3 M hydrochloric acid, and the solution was concentrated and purified by silica gel column chromatography (DCM / MeOH) to give a racemate of 4A (130 mg, yield: 88%) as a white solid. LCMS [M+1]+ = 626.1. Step 2: HATU (61 mg, 0.16 mmol) and DIEA (31 mg, 0.24 mmol) were added to a solution of the racemate of compound 4A (50 mg, 0.08 mmol) in DMF (3 mL), and N,O-dimethylhydroxylamine (16 mg, 0.16 mmol) was added under a N2 atmosphere. The mixture was stirred at room temperature for 3 h, concentrated, and purified by silica gel column chromatography (DCM / MeOH) to give a racemate of 4B (20 mg, yield: 38%) as a white solid. LCMS [M+1]+ = 669.2 Step 3: The racemate of compound 4B (12 mg, 0.02 mmol) was dissolved in a solution of THF / 6 M HCl (1 / 1, 4 mL). The resulting solution was stirred at room temperature for 1 h, concentrated, and purified by silica gel column chromatography (DCM / MeOH) to give a racemate of 4 (2.2 mg, yield: 22%) as a white solid, and the racemate was further resolved on a chiral column to give 4 as a white solid. LCMS [M+H]+ = 569.1. 1H NMR (400 MHz, DMSO) 8 8.25 (s, 1H), 7.53 (d, J = 8.5 Hz, 2H), 7.41 (s, 1H), 7.31 (d, J = 8.5 Hz, 2H), 7.20 (d, J = 0.9 Hz, 1H), 7.15 (s, 1H), 6.66 (t, J = 7.7 Hz, 1H), 6.21 (s, 1H), 6.16 (d, J = 7.9 Hz, 1H), 6.06 (d, J = 7.5 Hz, 1H), 5.61 (s, 1H), 5.07 (d, J = 4.8 Hz, 1H), 4.83 (s, 2H), 4.78 (t, J = 4.8 Hz, 1H), 4.32 (d, J = 13.9 Hz, 1H), 4.16 (s, 1H), 3.90 (s, 3H), 3.84 (s, 3H), 3.09 (s, 3H). Step 1: HATU (36.4 mg, 0.1 mmol) and DIEA (18.6 mg, 0.14 mmol) were mixed with a solution of the racemate of compound 4A (30 mg, 0.05 mmol) in DMF (3 mL) under N2, and O-methylhydroxylamine (8 mg, 0.10 mmol) was then added. The mixture was stirred at room temperature for 3 h, concentrated, and purified by silica gel column chromatography (DCM / MeOH) to give a racemate of 5A (20 mg, yield: 65%) as a white solid. LCMS [M+1]+ = 655.2. Step 2: The racemate of compound 5A (12 mg, 0.03 mmol) was dissolved in a solution of THF / 6 M HCl (1 / 1, 4 mL). The resulting solution was stirred at room temperature for 1 h, concentrated, and purified by silica gel column chromatography (DCM / MeOH) to give a racemate of 5 (2.6 mg, yield: 31%) as a white solid, and the racemate was further resolved on a chiral column to give compound 5. LCMS [M+H]+ = 555.1. 1H NMR (400 MHz, DMSO) 8 11.27 (s, 1H), 8.26 (s, 1H), 7.54 (d, J = 8.5 Hz, 2H), 7.42 (s, 1H), 7.30 (d, J = 8.3 Hz, 2H), 7.20 (s, 1H), 7.16 (s, 1H), 7.11 (t, J = 7.5 Hz, 1H), 6.87 (d, J = 18.2 Hz, 3H), 5.65 (s, 1H), 5.27 (s, 1H), 4.60 (d, J = 4.4 Hz, 1H), 4.46 (d, J = 13.9 Hz, 1H), 3.84 (s, 3H), 3.74 (dd, J = 14.1, 4.1 Hz, 1H), 3.54 (s, 3H). Compound 6 Step 1: The racemate of compound 4A (30.0 mg, 0.05 mmol), HATU (36.5 mg, 0.10 mmol), and DIEA (18.6 mg, 0.14 mmol) were stirred in DMF (3 mL) for 5 min. Dimethylamine hydrochloride (7.8 mg, 0.10 mmol) was added to the mixture, and the resulting mixture was stirred for 10 min. The solution was extracted with EA twice. The organic layer was washed with saturated brine, dried over Na2SO4, concentrated under reduced pressure, and purified by silica gel column chromatography (DCM / MeOH = 10 / 1) to give a racemate of compound 6A (16.0 mg, yield: 51%). LCMS [M+H]+ = 653.2. Step 2: The racemate of compound 6A (16.0 mg, 0.02 mmol) was mixed with THF (0.5 mL), and 6 M HCl (0.5 mL) was added at 0 °C. The mixture was stirred at room temperature for 4 h, concentrated, and purified by preparative high-performance liquid chromatography to give a racemate of 6 (5.9 mg, yield: 46%) as a white solid, and the racemate was further resolved on a chiral column to give compound 6. LCMS [M+H]+ = 553.2. 1H NMR (400 MHz, DMSO) 8 8.25 (s, 1H), 7.51 (d, J = 8.4 Hz, 2H), 7.41 (s, 1H), 7.35 (d, J = 8.4 Hz, 2H), 7.18 (d, J = 19.6 Hz, 2H), 6.73 (d, J = 7.4 Hz, 1H), 6.40-6.17 (m, 3H), 5.62 (s, 1H), 4.98 (s, 1H), 4.73 (s, 1H), 4.39 (d, J = 13.4 Hz, 1H), 4.15 (dd, J = 13.3, 4.9 Hz, 1H), 3.84 (s, 3H), 3.29 (s, 3H), 2.79 (s, 3H). Compound 7 CN                                     CN                                     CN 2H                                        7A                                         7 Step 1: The racemate of compound 2H (50 mg, 2.2 mmol), pyrazole (3.7 g, 13.3 mmol), tBuXPhos- Pd-G3 (4.8 mg, 0.01 mmol), tBuXPhos (12.78 mg, 0.03 mmol), and Cs2CO3 (67 mg, 0.21 mmol) were dissolved in 1,4-dioxane (2 mL). The reaction mixture was stirred at 100 °C for 16 h under a nitrogen atmosphere. After the reaction was complete, the reaction mixture was quenched with water and extracted with EA, followed by liquid separation. The organic phase was concentrated and then purified by silica gel column chromatography (DCM / EA = 1 / 1) to give a racemate of 7A (10 mg, yield: 20%) as a pale yellow solid. LCMS [M+H]+ = 639.2. Step 2: The racemate of compound 7A (10 mg, 0.016 mmol) was dissolved in THF (0.5 mL), and 6 M HCl (0.5 mL) was added. The mixture was stirred at room temperature for 4 h. The reaction solution was purified by flash column chromatography (ACN-H2O = 0-100%) to give a racemate of 7 (4 mg, yield: 47%) as a white solid, and the racemate was further resolved on a chiral column to give compound 7. LCMS [M+H]+ = 539.1. 1H NMR (400 MHz, DMSO) 8 8.58 (d, J = 2.4 Hz, 1H), 7.75 (d, J = 1.6 Hz, 1H), 7.51 (d, J = 8.4 Hz, 2H), 7.31 (d, J = 8.4 Hz, 2H), 7.13 (d, J = 1.6 Hz, 1H), 7.05 (d, J = 1.6 Hz, 1H), 6.68 (t, J = 7.6 Hz, 1H), 6.58-6.54 (m, 1H), 6.23 (s, 1H), 6.14 (m, 2H), 5.54 (s, 1H), 5.39 (d, J = 5.2 Hz, 1H), 4.82 (s, 2H), 4.64 (t, J = 5.2 Hz, 1H), 4.26 (d, J = 14.0 Hz, 1H), 3.95 (m, 1H), 3.82 (s, 3H), 3.58 (s, 3H). Compound 8 Step 1: Pd(PPh3)4 (9 mg, 0.0075 mmol) and CuI (28.5 mg, 0.015 mmol) were added to a solution of the racemate of compound 2H (54 mg, 0.075 mmol) and compound 8A (215 mg, 0.6 mmol) in DMF (5 mL). Then, the mixture was purged with nitrogen for 2 min, left to react under microwave conditions at 120 °C for 2 h, and concentrated, and the resulting crude product was purified by preparative column chromatography to give a racemate of 8B (20 mg, 40.9%) as a white solid. LCMS: [M+H-C4H8]+ = 595.2. Step 2: An aqueous HCl solution (0.5 mL, 6 M) was added to a solution of the racemate of compound 8B (20 mg, 0.0308 mmol) in THF (1 mL). The reaction solution was left to react at room temperature for 3 h and concentrated, and the resulting crude product was purified by preparative HPLC to give a racemate of 8 (9 mg, yield: 53.1%) as a white solid, and the racemate was further resolved on a chiral column to give compound 8. LCMS: [M+H]+ = 551.2. 1H NMR (400 MHz, DMSO) 8 9.53 (s, 2H), 8.94 (d, J = 4.9 Hz, 2H), 7.64 (d, J = 2.8 Hz, 2H), 7.55-7.43 (m, 3H), 7.36 (d, J = 8.6 Hz, 2H), 7.14 (t, J = 7.6 Hz, 1H), 7.06-6.82 (m, 3H), 5.66 (d, J = 58.4 Hz, 2H), 4.74 (d, J = 4.6 Hz, 1H), 4.41 (d, J = 13.8 Hz, 1H), 4.18 (d, J = 4.8 Hz, 1H), 3.86 (s, 3H), 3.60 (s, 3H). Compound 9 Step 1: After compound 1 (1.00 g, 2.21 mmol) and compound 9A (3.58 g, 22.08 mmol) were dissolved in a solution of TFE / trichloromethane (CHCl3 / TFE = 9 / 1, 18 mL), the solution was drawn into a 20 mL syringe mounted on a syringe pump, and the syringe pump was connected to an FEP tube. The FEP tube was sequentially wound around two quartz column sleeves, with a 250 W ultraviolet lamp tube in each quartz column sleeve. The two column sleeves were cooled to -5 °C using a low-temperature circulation pump, and a room-temperature water bath was added outside the entire lamp-column sleeve system. After the ultraviolet lamps were stably activated, the syringe pump was started to inject the reaction solution into the FEP tube at 30 mL / h, and the reaction solution was subjected to stable irradiation for 1 h. After the reaction was complete, the reaction solution was concentrated and separated by column chromatography (ethyl acetate / petroleum ether = 3 / 1) to remove the excess cinnamate starting material, giving a crude product. The crude product was diluted with ethyl acetate, and the mixture was left to react at 65 °C for 1 h and then concentrated to give a racemate of the target product 9B (crude, 0.96 g, yield: 71%) as a yellow oil. LCMS [M+H]+ = 615.5. Step 2: The racemate of compound 9B (1.4 g, 2.27 mmol) was dissolved in methanol (100 mL), and NaOMe (0.3 g, 5.7 mmol) was then added at 0 °C. Then, the reaction solution was left to react at 65 °C for 1 h, concentrated, and then separated by column chromatography (0.5% formic acid in ethyl acetate / petroleum ether = 1 / 3) to give a racemate of the target product 9C (0.96 g, yield: 68%) as a yellow oil. LCMS [M+H]+ = 615.1. Step 3: The racemate of compound 9C (0.60 g, 0.977 mmol) and AcOH (1.06 g, 17.586 mmol) were dissolved in MeCN (40 mL) and DCM (40 mL), and the solution was then cooled to 0 °C and placed under a N2 atmosphere. STAB (1.04 g, 4.89 mmol) was added in portions, and the mixture was stirred at room temperature for 1 h. The reaction solution was quenched with water. An aqueous NaHCO3 solution was added, and the mixture was extracted with DCM twice. The organic layer was dried, concentrated under reduced pressure, and purified by silica gel column chromatography (PE:EA) to give a racemate of 9D (0.32 g, yield: 53%) as a white solid. LCMS: [M+H]+ = 617.2. Step 4: The racemate of compound 9D (2.00 g, 3.24 mmol), Cs2CO3 (1.58 g, 4.86 mmol), and MeOH (0.21 g, 6.48 mmol) were dissolved in toluene (30 mL), and tBuXPhos Pd G3 (51 mg, 0.06 mmol) was then added. The mixture was heated to 85 °C and left to react for 3 h. The reaction solution was concentrated, diluted with a solution of MeOH / DCM (MeOH / DCM = 1 / 1), and filtered. The filtrate was concentrated and then separated by column chromatography (EA / PE = 60%) to give a racemate of the target product 9E (810 mg, yield: 44%) as a brown oil. LCMS: [M-H]- = 567.0. Step 5: The racemate of compound 9E (300 mg, 0.53 mmol) and Pd / C (10%, 150 mg) were dissolved in MeOH (15 mL), and the solution was then left to react at room temperature for 2 h under a H2 atmosphere. The reaction solution was filtered, and the filtrate was concentrated and then separated by column chromatography to give a racemate of the target product 9F (270 mg, crude, yield not calculated) as a white solid. LCMS: [M+H]+ = 479.4. Step 6: The racemate of compound 9F (360 mg, 0.75 mmol), compound 2G (268 mg, 0.75 mmol), and K2CO3 (207 mg, 1.5 mmol) were added to 5 mL of DMF, and the mixture was stirred at 60 °C for 1.5 h, cooled to room temperature, and extracted with ethyl acetate and water. The organic phase was isolated, dried over anhydrous Na2SO4, filtered, and then concentrated. The crude product was purified by silica gel column chromatography (EA / DCM, from 0 to 50%) to give a racemate of 9G (360 mg, yield: 78%) as a yellow solid. LCMS: [M-H]- = 609.2. Step 7: The racemate of compound 9G (340 mg, 0.56 mmol) was dissolved in DMF (5 mL), and compound 2I (1600 mg, 4.46 mmol), Pd(PPh3)4 (65 mg, 0.06 mmol), and CuI (21 mg, 0.11 mmol) were added. The mixture was left to react at 110 °C for 16 h under a nitrogen atmosphere. The reaction solution was cooled to room temperature and directly purified by silica gel column chromatography (PE / EA = 1 / 1) to give a racemate of 9H (180 mg, yield: 61%) as a white solid. LCMS [M+H]+ = 530.0. Step 8: MsCl (171 mL, 1.5 mmol) was added to a mixture of the racemate of compound 9H (80 mg, 0.15 mmol) and pyridine (0.5 mL) at 0 °C, and the resulting mixture was left to react at 0 °C for 1 h, diluted with ethyl acetate (5 mL), and washed with 1 M HCl (5 mL), followed by liquid separation. The organic phase was purified by silica gel column chromatography (DCM / EA = 1 / 1) to give a racemate of 9I (90 mg, yield: 97%) as a white solid. LCMS [M+H]+ = 608.1. Step 9: The racemate of compound 9I (90 mg, 0.15 mmol) was dissolved in DMF (0.5 mL), and NaCN (36 mg, 0.75 mmol) was added. The mixture was stirred at room temperature for 16 h and extracted with ethyl acetate. The organic phase was isolated, dried over anhydrous Na2SO4, filtered, and then concentrated. The crude product was purified by silica gel column chromatography (DCM / EA = 1 / 1) to give a racemate of 9J (70 mg, yield: 88%) as a white solid. LCMS [M+H]+ = 539.1. Step 10: The racemate of compound 9J (10 mg, 0.016 mmol) was dissolved in THF (0.5 mL), and a 2 M solution of lithium aluminum hydride in THF (0.08 mL) was added at 0 °C. The mixture was slowly warmed to room temperature and stirred for 1 h. The reaction solution was quenched with Na2SO4^10H2O, and the resulting mixture was filtered. The filtrate was purified by preparative medium-pressure column chromatography (ACN / H2O = 0%-100%, containing 0.1% formic acid) to give a racemate of 9 (7 mg, yield: 70%) as a white solid, and the racemate was further resolved on a chiral column to give compound 9. LCMS [M+H]+ = 515.1. 1H NMR (400 MHz, DMSO) 8 8.26 (s, 1H), 7.42 (s, 1H), 7.22 (d, J = 4.8 Hz, 2H), 7.13 (d, J = 8.4 Hz, 2H), 7.09-7.04 (m, 3H), 6.81-6.76 (m, 2H), 6.71 (d, J = 8.8 Hz, 2H), 3.97 (s, 3H), 3.66 (s, 3H), 3.23 (d, J = 13.6 Hz, 5H), 3.13 (m, 1H), 2.93 (s, 1H). Compound 10 10A Step 1 Step 2 Step 1: NaH (9.06 g, 234.6 mmol) was slowly added to a solution of 10A (12.11 g, 70 mmol) in THF (120 mL) at 0 °C. The mixture was stirred at room temperature for 0.5 h. Then, BnOH (16.2 g, 150 mmol) was added, and the mixture was stirred at room temperature for 3 h, slowly quenched 5 with water at 0 °C, and extracted with EtOAc. The organic phase was isolated, dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure to give compound 10B (19.6 g, yield: 89%). LCMS [M+H]+ = 317.2. Step 2: A MeMgBr solution (124.9 mL, 124.9 mmol) was slowly added dropwise to a solution of 10B (13.16 g, 41.6 mmol) in THF (150 mL) at -30 °C. Then, the mixture was stirred at room 10 temperature for 4.3 h, quenched with 6 N HCl, and stirred for another 2 h. The organic phase was washed with 1 N NaOH and water, isolated, dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography to give compound 10C (7.12 g, yield: 46%). LCMS [M+H]+ = 334.2. Step 3: Compound 10C (8.5 g, 25.5 mmol) was dissolved in EA (60 mL), and Pd(OH)2 (850 mg) 15 was added. The mixture was stirred at room temperature for 18 h under a hydrogen atmosphere and concentrated to give 10D (3.9 g, yield: 100%) as a white solid. LCMS [M+H]+ = 154.2. Step 4: BnBr (4.36 g, 25.5 mmol) was added dropwise to a solution of compound 10D (3.9 g, 25.5 mmol) and K2CO3 (9.85 g, 71.4 mmol) in acetone (40 mL), and the mixture was stirred at room temperature for 48 h, acidified with acetic acid, diluted with water, and extracted with EA. The organic layer was concentrated and washed with petroleum ether to give 10E (4.80 g, yield: 77%) as a yellowish-white solid. LCMS [M+H]+ = 244.1. Step 5: NaOH (2.368 g, 59.2 mmol) and 4-bromobenzaldehyde (3.65 g, 19.73 mol) were added to a solution of compound 10E (4800 mg, 19.73 mmol) in MeOH (60 mL). The reaction solution was stirred at 70 °C for 18 h, cooled, acidified with AcOH, and extracted with dichloromethane. The organic layer was washed with water and brine, dried, and concentrated. The crude product was slurried with PE / EA to give 10F (5.0 g, yield: 60%) as a white solid. LCMS [M+H]+ = 410.2. Step 6: NaOH (785 mg, 19.6 mmol, 7.0 eq) and H2O2 (12.5 mL) were added to a solution of compound 10F (1150 mg, 2.8 mmol, 1.0 eq) in MeOH / H2O (130 mL / 65 mL). The reaction solution was stirred at 50 °C for 3 h. The mixture was cooled and filtered. The solid was washed with a small amount of dichloromethane and acidified with AcOH, and extraction was performed with DCM. The organic layer was washed with water and brine, dried, and concentrated to give 10G (670 mg, yield: 57%) as a white solid. LCMS [M+H]+ = 424.0. 1H NMR (400 MHz, DMSO) 8 9.99 (s, 1H), 8.56 (d, J = 2.4 Hz, 1H), 8.18 (d, J = 8.8 Hz, 2H), 7.94 (d, J = 2.4 Hz, 1H), 7.80 (d, J = 8.8 Hz, 2H), 7.60-7.37 (m, 5H), 5.34 (s, 2H). Step 7: Compound 10G (2.5 g, 5.9 mmol) and compound 2A (9.8 g, 35.38 mmol) were dissolved in CHCl3 / TFE (7 / 3, 20 mL). A syringe was used to inject the reaction mixture at a rate of 12 mL / h through a syringe pump into a coil wound around a jacketed glass cylinder equipped with a 250 W ultraviolet lamp. The temperature of the external circulation cold trap was adjusted to keep the internal reaction temperature at 0-5 °C, and the UV lamp was turned on simultaneously. The reaction mixture was irradiated for 1 h and concentrated under reduced pressure to remove the solvent, and the residue was purified by silica gel column chromatography (EtOAc / hexane) to remove the excess cinnamate, giving a racemate of the product 10H (3.6 g, yield: 75%) as a light yellow oil. LCMS [M+H]+ = 700.9. Step 8: The racemate of compound 10H (2.5 g, 3.56 mmol) was dissolved in methanol (60 mL), and NaOMe (481 mg, 8.91 mmol) was then added at 0 °C. Subsequently, the reaction solution was stirred at 65 °C for 1.5 h. After the reaction was complete, the reaction solution was concentrated, extracted with EA, washed with water, an NH4Cl solution, and saturated brine, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and finally purified by silica gel column chromatography (0.2% FA, EA / PE = 1 / 3) to give a racemate of compound 10I (3.0 g, crude product). LCMS [M+H]+ = 701.0. Step 9: The racemate of compound 10I (3.0 g, 4.28 mmol) was dissolved in a mixed solvent of ACN / CHCl3 (1 / 1, 40 mL / 40 mL), and Na(AcO)3BH (4.533 g, 21.38 mmol) and AcOH (2.566 g, 47.0 mmol) were added at 0 °C. Then, the reaction solution was stirred at room temperature for 2 h. After the reaction was complete, the reaction solution was concentrated, extracted with EA, washed with water and saturated brine, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and finally purified by silica gel column chromatography (0.2% FA, EA / PE = 3 / 2) to give a racemate of compound 10J (500 mg). LCMS [M+H]+ = 703.0. 1H NMR (400 MHz, CDCI3) 8 8.06 (s, 1H), 7.86 (d, J = 1.9 Hz, 1H), 7.43 (d, J = 4.4 Hz, 4H), 7.40 (dd, J = 8.2, 5.0 Hz, 2H), 7.28 (s, 2H), 7.15 (d, J = 8.5 Hz, 1H), 7.10 (d, J = 2.0 Hz, 1H), 7.06 (d, J = 8.7 Hz, 2H), 7.00 (t, J = 7.9 Hz, 1H), 6.90 (s, 1H), 6.57 (d, J = 7.6 Hz, 1H), 6.35 (s, 1H), 5.14 (s, 2H), 5.06 (d, J = 6.0 Hz, 1H), 4.41 (d, J = 13.9 Hz, 1H), 3.95 (dd, J = 14.0, 6.0 Hz, 1H), 3.67 (s, 3H), 1.51 (s, 9H). Step 10: Pd2(dba)3 (128 mg, 0.14 mmol) was added to a solution of the racemate of compound 10J (500 mg, 0.71 mmol), DPPF (155 mg, 0.28 mmol), and Zn(CN)2 (208 mg, 1.80 mmol) in NMP (25 mL). The reaction solution was heated to 150 °C and left to react for 1.2 h under a N2 atmosphere, diluted with water, and extracted with EA. Then, the organic layer was washed with water and brine, dried, concentrated, and purified by silica gel column chromatography (EA / PE = 1 / 1) to give aracemate of10K (300 mg, yield: 65%) as a yellow solid. LCMS: [M+H]+ = 650.0. Step 11: Pd(OH)2 / C (10%, 0.1 g) was added to a solution of theracemate ofcompound 10K (300 mg, 0.46 mol) in EA / MeOH / THF / DCM (20:2:2:0.2, 7 mL). The mixture was stirred at room temperature for 18 h under a hydrogen atmosphere and filtered to remove the solid, and the filter cake was washed with MeOH / DCM (1 / 10). The combined filtrates were concentrated to give a racemate of 10L (0.22 g, yield: 87.0%) as a white solid. LCMS: [M+H]+ = 560.2. Step 12: K2CO3 (116 mg, 0.78 mmol) was added to a solution of the racemate ofcompound 10L (220 mg, 0.39 mmol) and compound 2G (150 mg, 0.39 mmol) in DMF (3 mL). The mixture was stirred at 60 °C for 1 h, quenched with water, and extracted with EtOAc. The organic phase was isolated, dried over anhydrous Na2SO4, filtered, and concentrated. The residue was purified by column chromatography (EA-PE / DCM = 0-50%) to give aracemate of10 M (221 mg, yield: 82%) as a yellow solid. LCMS [M+H-C4H8]+ = 636.1. Step 13: The racemate of compound 10M (70 mg, 0.1 mmol), compound 2I (280 mg, 0.8 mmol), Pd(PPh3)4 (12 mg, 0.01 mmol), and CuI (4 mg, 0.02 mmol) were added to DMF (3 mL), and the mixture was then stirred under microwave conditions at 135 °C for 5 h under a N2 atmosphere. Water was added, and the mixture was extracted with EA. The organic layer was washed with water and saturated brine and then dried and concentrated. The crude product was dissolved in DCM, and Boc2O (2 eq), DIPEA (3 eq), and DMAP (0.2 eq) were added. The mixture was stirred at 40 °C for 18 h, concentrated, and purified by flash chromatography (DCM / EA = 1:1, DCM:MeOH = 20:1) to give a racemate of 10N (60 mg, yield: 98%) as a white solid. LCMS [M+H]+ = 611.2. Step 14: H2O (2 mL), MeOH (2 mL), and LiOH (12.6 mg, 0.30 mmol) were added to a solution of the racemate of compound 10N (60 mg, 0.1 mmol) in THF (2 mL). Then, the mixture was stirred at room temperature for 5 h and purified by reversed-phase chromatography (MeCH / HCO2H / H2O) to give a racemate of 10O (30 mg, yield: 51%) as a white solid. LCMS [M+H]+ = 597.2. Step 15: The racemate of compound 10O (30 mg, 0.048 mmol), N,O-dimethylhydroxylamine (9 mg, 0.096 mmol), HATU (18 mg, 0.048 mmol), an...

Claims

1. A ligand-drug conjugate or a racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or a mixture thereof, or a pharmaceutically acceptable salt or solvate thereof, wherein the ligand-drug conjugate consists of a ligand, a linking group, and a drug group, and the drug group is selected from a structure represented by formula I-A, II-A', III-A', IV-A, or V-A:wherein:M is selected from -N(Rm)-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-N(Rm)-, wherein the -(C1-C6)alkylene-O- and -(C1-C6)alkylene-N(Rm)- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2;n is 0 or 1;W is absent or is selected from -(C1-C6)alkylene-, -O-, and -N(Rw)-, wherein the -(C1-C6)alkylene-is optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2;U is selected from -(C1-C6)alkylene-, -(C3-C6)cycloalkylene-, and -(4-10 membered)heterocyclylene-, wherein the -(C1-C6)alkylene-, -(C3-C6)cycloalkylene-, and -(4-10 membered)heterocyclylene- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2;Z is absent or is selected from -(C1-C6)alkylene-, -(C3-C6)cycloalkylene-, and -(4-10membered)heterocyclylene-;Y is absent or is selected from -O-, -N(Ry)-, and -N+(Ry)2-, wherein Ry is selected from hydrogen, -(C1-C6)alkyl, -O(C1-C6)alkyl, -(C1-C6)haloalkyl, and -O-(C1-C6)haloalkyl, or Ry and Z form -(410 membered)heterocyclylene-, wherein the -(4-10 membered)heterocyclylene- is optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2;R12 is selected from hydrogen, -(C1-C6)alkyl, -O-(C1-C6)alkyl, -(C=O)-(C1-C6)alkyl, -(C3-C6)cycloalkyl,   -O-(C3-C6)cycloalkyl,   -(4-10   membered)heterocyclyl,   and   -O-(4-10membered)heterocyclyl, wherein the -(C1-C6)alkyl, -O-(C1-C6)alkyl, -(C=O)-(C1-C6)alkyl, -(C3-C6)cycloalkyl,   -O-(C3-C6)cycloalkyl,   -(4-10   membered)heterocyclyl,   and   -O-(4-10membered)heterocyclyl are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2;L is absent or is selected from -C(=O)-(C1-C6)alkylene-O-, -C(=O)-(C1-C6)alkylene-N(RL)-, -C(=O)-(C1-C6)alkylene-N+(RL)2-, -C(=O)NH-(C1-C6)alkylene-O-, -C(=O)NH-(C1-C6)alkylene-N(RL)-, and -C(=O)NH-(C1-C6)alkylene-N+(RL)2-, wherein RL is selected from hydrogen, -(C1-C6)alkyl, -O-(C1-C6)alkyl, -(C1-C6)haloalkyl, and -O-(C1-C6)haloalkyl, wherein the -C(=O)-(C1-C6)alkylene-O-, -C(=O)-(C1-C6)alkylene-N(RL)-, -C(=O)-(C1-C6)alkylene-N+(RL)2-, -C(=O)NH-(C1-C6)alkylene-O-, -C(=O)NH-(C1-C6)alkylene-N(RL)-, and -C(=O)NH-(C1-C6)alkylene-N+(RL)2- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2;Q is selected from -N(Rq)-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-N(Rq)-, wherein the -(C1-C6)alkylene-O- and -(C1-C6)alkylene-N(Rq)- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2;T is selected from -N(Rt)-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-N(Rt)-, wherein the -(C1-C6)alkylene-O- and -(C1-C6)alkylene-N(Rq)- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2;Rm, Rw, Rq, and Rt are each independently selected from hydrogen, -(C1-C6)alkyl, -O-(C1-C6)alkyl, -(C1-C6)haloalkyl, and -O-(C1-C6)haloalkyl;X1 is selected from N and C(R1), wherein R1 is selected from hydrogen, halogen, cyano, -OH, -(C1-C6)alkyl, and -O-(C1-C6)alkyl;X2 is selected from N and C(R2), wherein R2 is selected from hydrogen, halogen, cyano, -OH, -(C1-C6)alkyl, and -O-(C1-C6)alkyl;R3 is selected from -(C3-C6)cycloalkyl, -(3-8 membered)heterocyclyl, -(C6-C10)aryl, and -(5-12membered)heteroaryl, wherein the -(C3-C6)cycloalkyl, -(3-8 membered)heterocyclyl, -(C6-C10)aryl, and -(5-12 membered)heteroaryl are optionally substituted with one or more R31;ring A is selected from -(C3-C6)cycloalkylene-, -(3-8 membered)heterocyclylene-, -(C6-C10)arylene-, and -(5-12 membered)heteroarylene-, wherein the -(C3-C6)cycloalkylene-, -(3-8 membered)heterocyclylene-, -(C6-C10)arylene-, and -(5-12 membered)heteroarylene- are optionally substituted with one or more R31;each R31 is independently selected from oxo, hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C6)alkyl, -(C1-C6)alkylene-OH, -(C1-C6)alkylene-NH2, -(C1-C6)alkylene-NH[(C1-C6)alkyl], -(C1-C6)alkylene-N[(C1-C6)alkyl]2, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl,     -(4-10 membered)heterocyclyl,     -O-(C3-C6)cycloalkyl,     -O-(4-10membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2, -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2, -(C6-C10)aryl, -(5-12 membered)heteroaryl, -S(=O)2-NH2, -S(=O)2-NH(C1-C6)alkyl, -S(=O)2-N[(C1-C6)alkyl]2, -NH-C(=O)H, -NH-C(=O)-(C1-C6)alkyl, -N[(C1-C6)alkyl]-C(=O)-(C1-C6)alkyl, N[(C1-C6)alkyl]-C(=O)H, -NH-S(=O)2-(C1-C6)alkyl, -N[(C1-C6)alkyl]-S(=O)2-(C1-C6)alkyl, -P(=O)[(C1-C6)alkyl]2, -P(=O)[(C1-C6)alkyl]-NH2, -P(=O)[(C1-C6)alkyl]-NH(C1-C6)alkyl, and -P(=O)[(C1-C6)alkyl]-N[(C1-C6)alkyl]2, wherein the -(C1-C6)alkyl, -(C1-C6)alkylene-OH, -(C1-C6)alkylene-NH2, -(C1-C6)alkylene-NH[(C1-C6)alkyl], -(C1-C6)alkylene-N[(C1-C6)alkyl]2, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2, -(C6-C10)aryl, -(5-12 membered)heteroaryl, -S(=O)2-NH2, -S(=O)2-NH(C1-C6)alkyl, -S(=O)2-N[(C1-C6)alkyl]2, -NH-C(=O)H, -NH-C(=O)-(C1-C6)alkyl, -N[(C1-C6)alkyl]-C(=O)-(C1-C6)alkyl, N[(C1-C6)alkyl]-C(=O)H, -NH-S(=O)2-(C1-C6)alkyl, -N[(C1-C6)alkyl]-S(=O)2-(C1-C6)alkyl, -P(=O)[(C1-C6)alkyl]2, -P(=O)[(C1-C6)alkyl]-NH2, -P(=O)[(C1-C6)alkyl]-NH(C1-C6)alkyl, and -P(=O)[(C1-C6)alkyl]-N[(C1-C6)alkyl]2 are optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -(C1-C6)alkylene-OH, -NH2, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C1-C6)alkylene-NH2, -(C1-C6)alkylene-NH[(C1-C6)alkyl], -(C1-C6)alkylene-N[(C1-C6)alkyl]2, -(C6-C10)aryl, -(5-12 membered)heteroaryl, -(C1-C6)alkylene-O(C1-C6)alkyl, and oxo;R4 is selected from hydrogen, halogen, cyano, -OH, -NH2, -(C1-C6)alkyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -(C3-C6)cycloalkyl, -O-(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(4-10 membered)heterocyclyl, -(C6-C10)aryl, -O-(C6-C10)aryl, -(5-12 membered)heteroaryl, and -O-(5-12 membered)heteroaryl;X is selected from O, S, NH, N[(C1-C6)alkyl], N[C(=O)-Rc], C(Ra)(Rb), C(=O), C[=C(Ra)Rb], S(=O), and S(=O)2;Ra and Rb are each independently selected from hydrogen, halogen, cyano, -ORc, -SRc, -N(Rc)Rc, -(C1-C6)alkyl, and -(C1-C6)haloalkyl;Rc is selected from hydrogen, -(C1-C6)alkyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -(C3-C6)cycloalkyl, -O-(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(4-10 membered)heterocyclyl, -(C6-C10)aryl, -O-(C6-C10)aryl, -(5-12 membered)heteroaryl, and -O-(512 membered)heteroaryl;ring B is selected from -(C6-C10)aryl and -(5-12 membered)heteroaryl, or ring B is selected from -(C6-C10)arylene- and -(5-12 membered)heteroarylene-, wherein the -(C6-C10)arylene- and -(5-12 membered)heteroarylene- are optionally substituted with one or more groups selected from R5 and R6;R5 and R6 are each independently selected from hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2, -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2, -C(=O)-H, and -C(=N-OH)-H, wherein the -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH(C1-C6)alkyl, and -C(=O)-N[(C1-C6)alkyl]2 are optionally substituted with one or more groups selected from hydrogen, halogen, oxo, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and N[(C1-C4)alkyl]2; orR5 and R6, together with the carbon atoms to which they are attached, form 5-membered heterocyclyl;ring C is selected from -(C6-C10)aryl and -(5-12 membered)heteroaryl, or ring C is selected from -(C6-C10)arylene- and -(5-12 membered)heteroarylene-, wherein the -(C6-C10)arylene- and -(5-12 membered)heteroarylene- are optionally substituted with one or more R7;each R7 is independently selected from hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2, -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2, and -NHC(=O)-(C1-C6)alkyl,wherein the -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -NH(C1-C6)alkyl, -N[(C1-C6)alkyl]2, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2, and -NHC(=O)-(C1-C6)alkyl are optionally substituted with one or more groups selected from hydrogen, halogen, oxo, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2;m is 1, 2, 3, 4, or 5;R8a, R8b, R9a, and R9b are each independently selected from hydrogen, halogen, cyano, -(C1-C6)alkyl, -(C1-C6)haloalkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -OR, -N(R)R, -[(C1-C8)alkylene]R, -[(C1-C8)alkylene]OR, -[(C1-C8)alkylene]N(R)R, -[(C1-C8)alkylene]N(R)C(=O)R, -[(C1-C8)alkylene]N(R)C(=O)N(R)R, -C(=O)R, -C(=O)N(R)R, -C(=O)[(C1-C8)alkylene]N(R)R, -C(=O)OR, -C(=S)N(R)R, -SR, -S(=O)R, -S(=O)2R, -S(=O)2N(R)R, -N(R)C(=O)R, -N(R)C(=O)N(R)R, -P(=O)(OR)(OR), -(C6-C10)aryl, -(5-12 membered)heteroaryl, -(C3-C6)cycloalkyl, and -(4-10 membered)heterocyclyl,wherein each R is independently selected from hydrogen, -OH, -NH2, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -(C1-C4)alkylene-O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -S(=O)2-(C1-C6)alkyl, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-H, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2,   -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2,   -[(C1-C6)alkylene]-(C3-C6)cycloalkyl,-[(C1-C6)alkylene]-(4-10 membered)heterocyclyl, -(C6-C10)aryl,-[(C1-C6)alkylene]-(C6-C10)aryl, and -(5-12 membered)heteroaryl, wherein the -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C1-C6)haloalkyl, -O-(C1-C6)alkyl, -(C1-C4)alkylene-O-(C1-C6)alkyl, -O-(C1-C6)haloalkyl, -S-(C1-C6)alkyl, -S(=O)2-(C1-C6)alkyl, -(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-10 membered)heterocyclyl, -C(=O)-(C1-C6)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C6)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH(C1-C6)alkyl, -C(=O)-N[(C1-C6)alkyl]2, -[(C1-C6)alkylene]-(C3-C6)cycloalkyl, -[(C1-C6)alkylene]-(4-10 membered)heterocyclyl, -(C6-C10)aryl, -[(C1-C6)alkylene]-(C6-C10)aryl, and -(5-12 membered)heteroaryl are optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, N[(C1-C4)alkyl]2, and (C1-C4)alkyl;or R8a and R8b are combined to form oxo, -(C2-C6)alkenyl, -(C3-C6)cycloalkyl, or -(4-10 membered)heterocyclyl;or R9a and R9b are combined to form oxo, -(C2-C6)alkenyl, -(C3-C6)cycloalkyl, or -(4-10 membered)heterocyclyl;or R8a and R9a, together with the carbon atoms to which they are attached, form (C3-C6)cycloalkyl, (4-10 membered)heterocyclyl, or (5-10 membered)heteroaryl, wherein the aforementioned group is optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2,    -(C3-C6)cycloalkyl,    -(4-8membered)heterocyclyl, -(5-6 membered)heteroaryl, and -(C6-C10)aryl;or R8b and R9b, together with the carbon atoms to which they are attached, form (C3-C6)cycloalkyl, (4-10 membered)heterocyclyl, or (5-10 membered)heteroaryl, wherein the aforementioned group is optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2,    -(C3-C6)cycloalkyl,    -(4-8membered)heterocyclyl, -(5-6 membered)heteroaryl, and -(C6-C10)aryl;R10 is selected from hydrogen, cyano, -OH, and -NH2, or R10 and R9a, together with the atoms to which they are attached, form (5-6 membered)heterocyclyl, wherein the (5-6 membered)heterocyclyl is optionally substituted with one or more groups selected from hydrogen, halogen, -OH, -(C1-C4)alkyl, -(C3-C6)cycloalkyl, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2.

2. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to claim 1, wherein:Rm, Rw, Ry, Rq, and Rt are each independently selected from hydrogen, -(C1-C4)alkyl, -O-(C1-C4)alkyl, -(C1-C4)haloalkyl, and -O-(C1-C4)haloalkyl;preferably, Rm, Rw, Ry, Rq, and Rt are each independently selected from hydrogen, methyl, ethyl, propyl, -O-methyl, -O-ethyl, and -O-propyl;preferably, Rm, Rw, Ry, Rq, and Rt are each independently hydrogen and methyl;preferably, Rm, Rw, Ry, Rq, and Rt are each independently hydrogen.

3. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to claim 1 or 2, wherein:M is selected from -NH-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-NH-, wherein the -(C1-C6)alkylene-O- and -(C1-C6)alkylene-NH- are optionally substituted with 1, 2, or 3 groups selected from hydrogen, halogen, -OH, -O-methyl, -NH2, -NH-methyl, -N(methyl)2, and -N(ethyl)2;preferably, M is selected from -NH-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-NH-;preferably, M is selected from -NH-, -O-, -(C1-C4)alkylene-O-, and -(C1-C4)alkylene-NH-;preferably, M is selected from -NH-, -O-, -CH2O-, and -CH2NH-;preferably, M is selected from -NH-, -O-, *-CH2O-, and *-CH2NH-, wherein the * end is attachedto ring C;preferably, M is selected from -NH-.

4. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, ordiastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to claim 1 or 2, wherein:W is absent or is selected from -(C1-C6)alkylene-, -NH-, -N[(C1-C6)alkyl]-, and -N[O(C1-C6)alkyl]-;preferably, W is absent or is selected from -(C1-C4)alkylene, -NH-, and -N[-(C1-C4)alkyl]-;preferably, W is absent or is selected from methylene, ethylene, -NH-, -N(Me)-, and -N(Et)-;preferably, W is absent or is selected from -NH- and -N(Me)-;U is selected from    -(C1-C6)alkylene-,    -(C3-C6)cycloalkylene-,    and -(4-10membered)heterocyclylene-;preferably, U is selected from -(C1-C4)alkylene-, -(C3-C6)cycloalkylene-, and -(4-6 membered)heterocyclylene-;preferably, U is selected from methylene, ethylene, cyclopropylene, azetidinylene, andpyrrolidinylene;preferably, U is selected from methylene, ethylene, andpreferably, U is selected from methylene, ethylene,andwherein the *end is attached to W, and when W is absent, the * end is attached to carbonyl;Z is absent or is selected from -(C1-C4)alkylene-, -(C3-C6)cycloalkylene-, and -(4-6 membered)heterocyclylene-;preferably, Z is absent or is selected from methylene, ethylene, cyclopropylene, azetidinylene, and pyrrolidinylene;preferably, Z is absent;Y is absent or is selected from -O-, -N(Ry)-, and -N+(Ry)2-, wherein Ry is selected from hydrogen, -(C1-C6)alkyl, and -O(C1-C6)alkyl, or Ry and Z form -(4-10 membered)heterocyclylene-;preferably, Y is absent or is selected from -O-, -N(Ry)-, and -N+(Ry)2-, wherein Ry is selected from hydrogen, -(C1-C4)alkyl, and -O(C1-C4)alkyl, or Ry and Z form -(4-6 membered)heterocyclylene-; preferably, Y is absent or is selected from -O-, -N(Ry)-, and -N+(Ry)2-, wherein Ry is selected from hydrogen, methyl, ethyl, and -O-methyl;preferably, Y is selected from -O-, -NH-, -N(CH3)-, and -N+(CH3)2-.

5. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvatethereof according to claim 1 or 2, wherein:the structural unit -W-U-Z-Y- is selected from -N(Rw)-(C1-C6)alkylene-N(Ry)-, -N(Rw)-(C1-C6)alkylene-N+(Ry)2-, -N(Rw)-(C1-C6)alkylene-O-, -(C1-C6)alkylene-N(Ry)-, -(C1-C6)alkylene-O-, -(C3-C6)cycloalkylene-N(Ry)-, -(C1-C6)alkylene-N+(Ry)2-, -(C3-C6)cycloalkylene-O-, -(4-6 membered)heterocyclylene-O-, -(4-6 membered)heterocyclylene-N(Ry)-, and -N(Rw)-(4-6 membered)heterocyclylene-, wherein the -N(Rw)-(C1-C6)alkylene-N(Ry)-, -N(Rw)-(C1-C6)alkylene-N+(Ry)2-, -N(Rw)-(C1-C6)alkylene-O-, -(C1-C6)alkylene-N(Ry)-, -(C1-C6)alkylene-N+(Ry)2-, -(C1-C6)alkylene-O-, -(C3-C6)cycloalkylene-N(Ry)-, -(C3-C6)cycloalkylene-O-, -(4-6 membered)heterocyclylene-O-, -(4-6 membered)heterocyclylene-N(Ry)-, and -N(Rw)-(4-6 membered)heterocyclylene- are optionally substituted with one or more (e.g., 1, 2, 3, 4, 5, 6, or 7) groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2;preferably, the structural unit -W-U-Z-Y- is selected from -N(Rw)-(C1-C6)alkylene-N(Ry)-, -N(Rw)-(C1-C6)alkylene-N+(Ry)2-, -N(Rw)-(C1-C6)alkylene-O-, -(C1-C6)alkylene-N(Ry)-, -(C1-C6)alkylene-N+(Ry)2-, -(C1-C6)alkylene-O-, -(4-6 membered)heterocyclylene-O-, -(4-6 membered)heterocyclylene-N(Ry)-, and -N(Rw)-(4-6 membered)heterocyclylene-;preferably, the structural unit -W-U-Z-Y- is selected from *-NH-CH2-CH2-NH-, *-N(CH3)-CH2-CH2-NH-, *-NH-CH2-CH2-O-, *-CH2-O-, *-CH2-NH-, *-CH2-N(CH3)-, *-CH2-N+(CH3)2-, r~N * /   J—If N                            .                    .and H         , wherein the * end is attached to carbonyl.

6. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to claim 1 or 2, wherein:R12 is selected from hydrogen, -(C1-C6)alkyl, -O-(C1-C6)alkyl, -(C=O)-(C1-C6)alkyl, -(C3-C6)cycloalkyl, -O-(C3-C6)cycloalkyl, -(4-10 membered)heterocyclyl, and -O-(4-10 membered)heterocyclyl;preferably, R12 is selected from hydrogen, -(C1-C4)alkyl, -O-(C1-C4)alkyl, -(C=O)-(C1-C4)alkyl, -(C3-C6)cycloalkyl, and -O-(C3-C6)cycloalkyl;preferably, R12 is selected from hydrogen, -(C1-C4)alkyl, -O-(C1-C4)alkyl, and -(C3-C6)cycloalkyl;preferably, R12 is selected from hydrogen and -(C1-C4)alkyl;preferably, R12 is selected from hydrogen, methyl, and ethyl;preferably, R12 is selected from hydrogen and methyl;preferably, R12 is selected from hydrogen;L is absent or is selected from -C(=O)-(C1-C4)alkylene-O-, -C(=O)-(C1-C4)alkylene-N(RL)-, -C(=O)-(C1-C4)alkylene-N+(RL)2-, -C(=O)NH-(C1-C4)alkylene-O-, -C(=O)NH-(C1-C4)alkylene-N(RL)-, and -C(=O)NH-(C1-C4)alkylene-N+(RL)2-, wherein RL is selected from hydrogen, -(C1-C4)alkyl, and -(C1-C4)haloalkyl;preferably, L is absent or is selected from -C(=O)-(C1-C4)alkylene-O-, -C(=O)-(C1-C4)alkylene-N(RL)-, and -C(=O)-(C1-C4)alkylene-N+(RL)2-, wherein RL is selected from hydrogen, methyl, and ethyl;preferably, L is absent or is selected from -C(=O)CH2O-, -C(=O)CH2CH2O-, -C(=O)CH2N(RL)-, -C(=O)CH2CH2N(RL)-, -C(=O)CH2N+(RL)2-, and -C(=O)CH2CH2N+(RL)2-, wherein RL is selected from hydrogen, methyl, and ethyl;preferably, L is absent or is selected from *-C(=O)CH2O-, *-C(=O)CH2N(CH3)-, and *-C(=O)CH2N+(CH3)2-, wherein the * end is attached to N.

7. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to claim 1 or 2, wherein:Q is selected from -NH-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-NH-, wherein the -(C1-C6)alkylene-O- and -(C1-C6)alkylene-NH- are optionally substituted with 1, 2, or 3 groups selected from hydrogen, halogen, -OH, -O-methyl, -NH2, -NH-methyl, -N(methyl)2, and -N(ethyl)2;preferably, Q is selected from -NH-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-NH-; preferably,Q is selected from -NH-, -O-, -(C1-C4)alkylene-O-, and -(C1-C4)alkylene-NH-; preferably,Q is selected from -NH-, -O-, -CH2O-, and -CH2NH-;preferably,Q is selected from -NH-, -O-, *-CH2O-, and *-CH2NH-, wherein the * end is attached to ring B;preferably, Q is selected from -NH-.

8. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to claim 1 or 2, wherein:T is selected from -NH-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-NH-, wherein the -(C1-C6)alkylene-O- and -(C1-C6)alkylene-NH- are optionally substituted with 1, 2, or 3 groups selected from hydrogen, halogen, -OH, -O-methyl, -NH2, -NH-methyl, -N(methyl)2, and -N(ethyl)2;preferably, T is selected from -NH-, -O-, -(C1-C6)alkylene-O-, and -(C1-C6)alkylene-NH-;preferably, T is selected from -NH-, -O-, -(C1-C4)alkylene-O-, and -(C1-C4)alkylene-NH-;preferably, T is selected from -NH-, -O-, -CH2O-, and -CH2NH-;preferably, T is selected from -NH-, -O-, *-CH2O-, and *-CH2NH-, wherein the * end is attached to ring A;preferably, T is selected from -NH-, *-CH2O-, and *-CH2NH-, wherein the * end is attached to ring A;preferably, T is selected from -NH- and *-CH2NH-, wherein the * end is attached to ring A.

9. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-8, wherein R1 is selected from hydrogen, halogen, cyano, -OH, -(C1-C4)alkyl, and -O-(C1-C4)alkyl;preferably, R1 is selected from hydrogen, fluorine, chlorine, cyano, -OH, methyl, ethyl, propyl, -O-methyl, -O-ethyl, and -O-propyl;preferably, R1 is selected from hydrogen and -O-methyl;preferably, X1 is selected from N, CH, and C(OCH3).

10. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-9, wherein R2 is selected from hydrogen, halogen, cyano, -OH, -(C1-C4)alkyl, and -O-(C1-C4)alkyl;preferably, R2 is selected from hydrogen, fluorine, chlorine, cyano, -OH, methyl, ethyl, propyl, -O-methyl, -O-ethyl, and -O-propyl;preferably, R2 is hydrogen;preferably, X2 is selected from N and CH.

11. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-10, wherein:R3 is selected from -(C3-C6)cycloalkyl, -(4-6 membered)heterocyclyl, -(C6-C10)aryl, and -(5-12 membered)heteroaryl, wherein the -(C3-C6)cycloalkyl, -(4-6 membered)heterocyclyl, -(C6-C10)aryl, and -(5-12 membered)heteroaryl are optionally substituted with one or more R31;ring A is selected from -(C3-C6)cycloalkylene-, -(4-6 membered)heterocyclylene-, -(C6-C10)arylene-, and -(5-12 membered)heteroarylene-, wherein the -(C3-C6)cycloalkylene-, -(4-6 membered)heterocyclylene-, -(C6-C10)arylene-, and -(5-12 membered)heteroarylene- are optionally substituted with one or more R31;R31 is selected from oxo, hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C4)alkyl, -(C1-C4)alkylene-OH, -(C1-C4)alkylene-NH2, -(C1-C4)alkylene-NH(C1-C4)alkyl, -(C1-C4)alkylene-N[(C1-C4)alkyl]2, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, -(4-8membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-8 membered)heterocyclyl, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C4)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2, -C(=O)-NH(C1-C4)alkyl, and -C(=O)-N[(C1-C4)alkyl]2;preferably, R31 is selected from oxo, hydrogen, halogen, cyano, -OH, -SH, -NH2, -(C1-C4)alkyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -NH-(C1-C4)alkyl, -(C1-C4)alkylene-OH, -(C1-C4)alkylene-NH2, -(C1-C4)alkylene-NH(C1-C4)alkyl, and -(C1-C4)alkylene-N[(C1-C4)alkyl]2;preferably, R31 is selected from oxo, hydrogen, fluorine, chlorine, cyano, -OH, -SH, -NH2, methyl, halomethyl, -O-methyl, -CH2OH, -CH2NH2, and -CH2CH2N(CH3)2;preferably, R31 is selected from hydrogen, -NH2, -CH2OH, and -CH2NH2;preferably, R31 is selected from hydrogen;preferably, R3 is selected from -(C3-C6)cycloalkyl and -(4-6 membered)heterocyclyl, wherein the -(C3-C6)cycloalkyl and -(4-6 membered)heterocyclyl are optionally substituted with one or more R31, wherein R31 is defined as described in the present claim;preferably, R3 is selected from cyclopropyl, oxetanyl, tetrahydrofuranyl, azetidinyl, pyrrolidinyl, morpholinyl, morpholinonyl, piperidinyl, piperazinyl, and piperazinonyl, wherein the cyclopropyl, oxetanyl, tetrahydrofuranyl, azetidinyl, pyrrolidinyl, morpholinyl, morpholinonyl, piperidinyl, piperazinyl, and piperazinonyl are optionally substituted with 1, 2, or 3 R31, wherein R31 is defined as described in the present claim;preferably, R3 is selected from Opreferably, R3 is selected from phenyl, naphthyl, and -(5-10 membered)heteroaryl, wherein the phenyl, naphthyl, and -(5-10 membered)heteroaryl are optionally substituted with one or more R31, wherein R31 is defined as described in the present claim;preferably, R3 is selected from -(5-9 membered)heteroaryl, wherein the -(5-9 membered)heteroaryl is optionally substituted with 1, 2, 3, or 4 R31, wherein R31 is defined as described in the present claim;preferably, R3 is selected from oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyrazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrazinyl, pyridazinyl, pyrimidinyl, pyridazinoimidazolyl, pyrazinoimidazolyl, and pyrimidinonyl, wherein the oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyrazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrazinyl, pyridazinyl, pyrimidinyl, pyridazinoimidazolyl, pyrazinoimidazolyl, and pyrimidinonyl are optionally substituted with 1, 2, or 3 R31, wherein R31 is defined as described in the present claim;preferably, R3 is selected from Ni NN'Nand ^''O ,wherein theN=Nand'O are optionallysubstituted with 1, 2, or 3 R31, wherein R31 is defined as described in the present claim;, and 0more preferably, R3 is selected frompreferably, ring A is selected from phenylene, naphthylene, and -(5-10 membered)heteroarylene-, wherein the phenylene, naphthylene, and -(5-10 membered)heteroarylene- are optionally substituted with one or more R31, wherein R31 is defined as described in the present claim;preferably, ring A is selected from -(5-9 membered)heteroarylene-, wherein the -(5-9 membered)heteroarylene- is optionally substituted with 1, 2, 3, or 4 R31, wherein R31 is defined as described in the present claim;preferably, ring A is selected from -(5-6 membered)heteroarylene-, wherein the -(5-6 membered)heteroarylene- is optionally substituted with 1, 2, 3, or 4 R31, wherein R31 is defined as described in the present claim;preferably, ring A is selected from oxazolylene, isoxazolylene, thiazolylene, isothiazolylene,pyrazolylene, imidazolylene, triazolylene, tetrazolylene, pyridinylene, pyrazinylene, pyridazinylene, pyrimidinylene, pyridazinoimidazolylene, pyrazinoimidazolylene, and pyrimidinonylene, wherein the oxazolylene, isoxazolylene, thiazolylene, isothiazolylene,pyrazolylene, imidazolylene, triazolylene, tetrazolylene, pyridinylene, pyrazinylene,pyridazinylene, pyrimidinylene, pyridazinoimidazolylene, pyrazinoimidazolylene, andpyrimidinonylene are optionally substituted with 1, 2, or 3 R31, wherein R31 is defined as describedin the present claim;*Hz<H             *HOHpreferably, ring A is selected from N ,              ,    \=N    , N* / 4—1<fZVH <f yHN-N , and ' N , wherein the * end is attached to T;preferably, ring A is selected from* / 1iOh * hCA-N , N , and ' Nwherein the * end is attached to T.

12. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-11, wherein R4 is selected from hydrogen, halogen, cyano, -OH, -NH2, -(C1-C4)alkyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, and -O-(C1-C4)haloalkyl;preferably, R4 is selected from hydrogen, fluorine, chlorine, cyano, -OH, -NH2, and methyl; preferably, R4 is hydrogen.

13. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-12, wherein X is selected from O, S, NH, N[(C1-C4)alkyl], N[C(=O)-Rc], C(Ra)(Rb), C(=O), C[=C(Ra)Rb], S(=O), and S(=O)2, wherein Ra and Rb are each independently selected from hydrogen, halogen, cyano, -ORc, -SRc, -N(Rc)Rc, -(C1-C4)alkyl, and -(C1-C4)haloalkyl, wherein Rc is selected from hydrogen, -(C1-C4)alkyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, and -(C3-C6)cycloalkyl;preferably, X is selected from O, S, NH, and N[(C1-C4)alkyl];preferably, X is selected from O, S, and NH;more preferably, X is selected from O.

14. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-13, wherein ring B is selected from -(C6-C10)aryl and (510 membered)heteroaryl, or ring B is selected from -(C6-C10)arylene- and (5-10 membered)heteroarylene-, wherein the -(C6-C10)arylene- and (5-10 membered)heteroarylene- are optionally substituted with 1, 2, or 3 groups selected from R5 and R6;preferably, ring B is selected from phenyl, naphthyl, and (5-6 membered)heteroaryl;a     >=<preferably, the structural unit R5               is R5 R6; orpreferably, ring B is selected from phenylene, naphthylene, and (5-6 membered)heteroarylene, wherein the phenylene, naphthylene, and (5-6 membered)heteroarylene are optionally substituted with 1 or 2 groups selected from R5 and R6;preferably, ring B is phenylene, wherein the phenylene is optionally substituted with 1 R5 or R6;preferably, ring B is         , wherein the * end is attached to Q;R5 and R6 are each independently selected from hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, and -O-(4-8 membered)heterocyclyl, wherein the-(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, and -O-(4-8 membered)heterocyclyl are optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and N[(C1-C4)alkyl]2;preferably, R5 and R6 are each independently selected from hydrogen, halogen, cyano, -OH, -NH2, -(C1-C4)alkyl, -(C1-C4)alkyl-OH, -(C1-C4)alkyl-NH2, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, and -(C3-C6)cycloalkyl;preferably, R5 is selected from hydrogen, fluorine, chlorine, bromine, cyano, -OH, -NH2, and -CH2NH2;preferably, R5 is selected from hydrogen, -OH, -NH2, and -CH2NH2;preferably, R6 is selected from hydrogen, fluorine, chlorine, bromine, cyano, -OH, -NH2, -O-methyl, and cyclopropyl;.5                     ................. 0    '     .or R5 and R6, together with the atoms to which they are attached, form , wherein * indicates the position of the attached atom.

15. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvatethereof according to any one of claims 1-14, wherein ring C is selected from -(C6-C10)aryl and (510 membered)heteroaryl, or ring C is selected from -(C6-C10)arylene and (5-10 membered)heteroarylene, wherein the -(C6-C10)arylene and (5-10 membered)heteroarylene are optionally substituted with 1, 2, or 3 R7;preferably, ring C is selected from phenyl, naphthyl, and (5-6 membered)heteroaryl;c j—(R7)m T T 1 JL 7preferably, the structural unit                     is               or           R ; orpreferably, ring C is selected from phenylene, naphthylene, and (5-6 membered)heteroarylene, wherein the phenylene, naphthylene, and (5-6 membered)heteroarylene are optionally substituted with 1 or 2 R7;preferably, ring C is phenylene, wherein the phenylene is optionally substituted with 1 R7; / \ * . . . .preferably, ring C is             , wherein the * end is attached to M;each R7 is independently selected from hydrogen, halogen, cyano, nitro, -OH, -SH, -NH2, -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, -(4-8membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-8 membered)heterocyclyl, and -NHC(=O)-(C1-C4)alkyl, wherein the -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -S-(C1-C4)alkyl, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl,      -(4-8 membered)heterocyclyl,      -O-(C3-C6)cycloalkyl,      -O-(4-8membered)heterocyclyl, and -NHC(=O)-(C1-C4)alkyl are optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2;preferably, each R7 is independently selected from hydrogen, halogen, cyano, -OH, -NH2, -(C1-C4)alkylene-OH, -(C1-C4)alkylene-NH(C1-C4)alkyl, -(C1-C4)alkylene-N[(C1-C4)alkyl]2, -(C1-C4)alkylene-NH2, and -NHC(=O)-(C1-C4)alkylene-NH2;preferably, each R7 is independently selected from hydrogen, fluorine, chlorine, bromine, -OH, -NH2, -CH2OH, -CH2NH2, -NHC(=O)CH2NH2, and -NHC(=O)CH2CH2NH2;preferably, each R7 is independently selected from hydrogen;preferably, m is 1, 2, or 3.

16. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-15, wherein R8a, R8b, R9a, and R9b are each independently selected from hydrogen, halogen, cyano, -(C1-C4)alkyl, -(C1-C4)haloalkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -OR, -N(R)R, -[(C1-C6)alkylene]R, -[(C1-C6)alkylene]OR, -[(C1-C6)alkylene]N(R)R, -[(C1-C6)alkylene]N(R)C(=O)R, -[(C1-C6)alkylene]N(R)C(=O)N(R)R, -C(=O)R, -C(=O)N(R)R, -C(=O)[(C1-C6)alkylene]N(R)R, -C(=O)OR, -C(=S)N(R)R, -SR, -S(=O)R, -S(=O)2R, -S(=O)2N(R)R, -N(R)C(=O)R, -N(R)C(=O)N(R)R, and -P(=O)(OR)(OR); each R is independently selected from hydrogen, -OH, -NH2, -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -(C1-C4)alkylene-O-(C1-C4)alkyl, -S-(C1-C4)alkyl, -S(=O)2-(C1-C4)alkyl, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-8 membered)heterocyclyl, -C(=O)-H, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C4)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH2, -C(=O)-NH(C1-C4)alkyl, -[(C1-C4)alkylene]-(C3-C6)cycloalkyl, -C(=O)-N[(C1-C4)alkyl]2, -[(C1-C4)alkylene]-(4-8 membered)heterocyclyl, -(C6-C10)aryl, -[(C1-C4)alkylene]-(C6-C10)aryl, and -(5-10 membered)heteroaryl, wherein the -(C1-C4)alkyl, -(C2-C4)alkenyl, -(C2-C4)alkynyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -O-(C1-C4)haloalkyl, -(C1-C4)alkylene-O-(C1-C4)alkyl, -S-(C1-C4)alkyl, -S(=O)2-(C1-C4)alkyl, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -O-(C3-C6)cycloalkyl, -O-(4-8 membered)heterocyclyl, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, -C(=O)-O-(C1-C4)alkyl, -C(=O)-O-(C3-C6)cycloalkyl, -C(=O)-NH(C1-C4)alkyl, -[(C1-C4)alkylene]-(C3-C6)cycloalkyl,        -C(=O)-N[(C1-C4)alkyl]2,        -[(C1-C4)alkylene]-(4-8membered)heterocyclyl, -(C6-C10)aryl, -[(C1-C4)alkylene]-(C6-C10)aryl, and -(5-10 membered)heteroaryl are optionally substituted with 1, 2, 3, 4, 5, 6, or 7 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, N[(C1-C4)alkyl]2, and (C1-C4)alkyl;preferably, each R is independently selected from hydrogen, -OH, -NH2, -(C1-C4)alkyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -(C1-C4)alkylene-O-(C1-C6)alkyl, -O-(C1-C4)haloalkyl, -S(=O)2-(C1-C4)alkyl, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -C(=O)-H, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, -[(C1-C4)alkylene]-(C3-C6)cycloalkyl, and -[(C1-C4)alkylene]-(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl, -(C1-C4)haloalkyl, -O-(C1-C4)alkyl, -(C1-C4)alkylene-O-(C1-C6)alkyl, -O-(C1-C4)haloalkyl, -S(=O)2-(C1-C4)alkyl, -(C3-C6)cycloalkyl, -(48 membered)heterocyclyl, -C(=O)-(C1-C4)alkyl, -C(=O)-(C3-C6)cycloalkyl, -[(C1-C4)alkylene]-(C3-C6)cycloalkyl, and -[(C1-C4)alkylene]-(4-8 membered)heterocyclyl are optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, N[(C1-C4)alkyl]2, methyl, and ethyl;preferably, each R is independently selected from hydrogen, -OH, -NH2, -CH3, -CH2CH3, -CH2OH, -CH2CH2OH, -CH2OCH3, -CH2NH2, -CH2CH2NH2, -CH2CH2NHCH3, -CH2N(CH3)2, -CH(N(CH3)2)CH2OH, -CH2OCH2CH2OH, -OCH3, -C(=O)-H, -C(=O)CH3, -C(=O)CH2OH, -S(=O)2CH3, cyclobutyl-OH, oxetanyl, azetidinyl, azetidinyl-OH, pyrrolidinyl, piperazinyl, azetidinyl-CH3, piperazinyl-CH3, and -CH2-azetidinyl;more preferably, each R is independently selected from hydrogen, -OH, -NH2, -(C1-C4)alkyl, -O-(C1-C4)alkyl, and -(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl, -O-(C1-C4)alkyl, and -(4-8 membered)heterocyclyl are optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -NH2, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, and -O-(C1-C4)alkyl;more preferably, each R is independently selected from hydrogen, -OH, -(C1-C4)alkyl, -O-(C1-C4)alkyl, and -(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl, -O-(C1-C4)alkyl, and -(4-8 membered)heterocyclyl are optionally substituted with 1, 2, or 3 groups selected from hydrogen, halogen, -OH, -NH2, -NH-methyl, and -N(methyl)2;more preferably, each R is independently selected from methyl, ethyl, propyl, -O-methyl, -O-ethyl, -O-propyl, oxetanyl, and azetidinyl, wherein the aforementioned groups are each independently and optionally substituted with 1, 2, or 3 groups selected from -OH and -NH2;preferably, R8a, R8b, R9a, and R9b are each independently selected from hydrogen, cyano, -OR, -N(R)R, -[(C1-C4)alkylene]R, -[(C1-C4)alkylene]OR, -[(C1-C4)alkylene]N(R)R, -[(C1-C4)alkylene]N(R)C(=O)R, -[(C1-C4)alkylene]N(R)C(=O)N(R)R, -C(=O)R, -C(=O)N(R)R, -C(=O)[(C1-C4)alkylene]N(R)R, -C(=O)OR, -C(=S)N(R)R, -S(=O)R, -S(=O)2R, -S(=O)2N(R)R, -N(R)C(=O)R, and -N(R)C(=O)N(R)R, wherein R is defined as described in the present claim;preferably, R8a and R8b are each independently selected from hydrogen, -methylene-R, -ethylene-R, -propylene-R, -methylene-OR, -ethylene-OR, -propylene-OR, -methylene-N(R)R, -ethylene-N(R)R, -propylene-N(R)R, -C(=O)R, -C(=O)N(R)R, and -C(=O)OR, wherein R is defined as described in the present claim;preferably, R8a and R8b are each independently selected from hydrogen, -methylene-R, -methylene-OR, -methylene-N(R)R, -C(=O)R, -C(=O)OR, and -C(=O)N(R)R, wherein R is defined as described in the present claim; for example, each R is independently selected from hydrogen, -OH, -NH2, -(C1-C4)alkyl, -O-(C1-C4)alkyl, -C(=O)-(C1-C4)alkyl, -S(=O)2(C1-C4)alkyl, and -(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl and -(4-8 membered)heterocyclyl are each optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -NH2, -NHCH3, and CH3;preferably, R8a is hydrogen, preferablypreferably, R8b is selected from hydrogen,preferably, R8b is selected from hydrogen,o r-o o r-NHV N     V NX H , and X H ;preferably, R9a and R9b are each independently selected from hydrogen, -CN, -OR, -NHR, -N(R)R, -NHC(=O)R, -methylene-R, -ethylene-R, -propylene-R, -methylene-N(R)R, -ethylene-N(R)R, -propylene-N(R)R, -methylene-NHC(=O)R, and -methylene-NHC(=O)NHR, wherein R is defined as described in the present claim;preferably, R9a and R9b are each independently selected from hydrogen, -CN, -OR, -N(R)R, -NHC(=O)R, -methylene-N(R)R, -methylene-NHC(=O)R, and -methylene-NHC(=O)NHR, wherein R is defined as described in the present claim; for example, each R is independently selected from hydrogen, -OH, -(C1-C4)alkyl, -(C1-C4)alkylene-O-(C1-C4)alkyl, -S(=O)2(C1-C4)alkyl, -(C3-C6)cycloalkyl, -(4-8 membered)heterocyclyl, -methylene-(C3-C6)cycloalkyl, and -methylene-(4-8 membered)heterocyclyl, wherein the -(C1-C4)alkyl, -(C3-C6)cycloalkyl, and -(4-8 membered)heterocyclyl are each optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -NH2, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -O-(C1-C4)alkyl, and -(C1-C4)alkyl;preferably, R9a is selected from hydrogen, -CN, -N(R)R, -NHC(=O)R, -methylene-N(R)R, -methylene-NHC(=O)R, and -methylene-NHC(=O)NHR, wherein R is defined as described in the present claim; for example, each R is independently selected from hydrogen, -OH, methyl, ethyl, -methylene-O-ethyl, -S(=O)2-methyl, cyclobutyl, azetidinyl, -methylene-cyclobutyl, and -methylene-azetidinyl, wherein the aforementioned groups are each independently and optionally substituted with 1, 2, or 3 groups selected from -OH, OCH3, NHCH3, N(CH3)2, and CH3;preferably, R9a is selected from hydrogen, -CN, -NHCH3, -N(CH3)2, -NHC(=O)H, -NHC(=O)CH2OH, -NHC(=O)CH2OCH3, -NHC(=O)CH2NHCH3, -NHC(=O)CH2N(CH3)2, -CH2NH2, -CH2NHCH3, -CH2N(CH3)2, -CH2N(CH2CH3)2, -CH2N(CH3)(CH2CH3),  -CH2NHC(=O)CH2OH,    -CH2NHC(=O)CH2OCH3,    -CH2NHC(=O)CH2NHCH3,    -CH2NHC(=O)CH2N(CH3)2, -CH2NHC(=O)H, -CH2NHC(=O)CH3, -CH2NHC(=O)NHOH, -CH2NHC(=O)NHCH2CH2OH, -CH2NHC(=O)CH(N(CH3)2)CH2OH, -CH2NHC(=O)CH2NHCH3, -CH2NHC(=O)CH2N(CH3)2, -CH2NHC(=O)CH2N(CH2CH3)2, -CH2NHC(=O)CH2OCH2CH2OH, -CH2NHS(=O)2CH3, -CH2NHC(=O)cyclobutyl-OH, -CH2NHC(=O)-azetidinyl-CH3, and -CH2NHC(=O)CH2-azetidinyl; /      V'0' O-NC "N HN       hn        hnpreferably, R9a is selected from hydrogen, -^, -^,            ,            ,            ,preferably, R9a isHQpreferably, R9b is selected from hydrogen and --=-HQ preferably, R9b is -OH, preferably ;or R8a and R8b are combined to form oxo,-(C2-C4)alkenyl, -(C3-C6)cycloalkyl, or -(4-8membered)heterocyclyl;or R9a and R9b are combined to form oxo,-(C2-C4)alkenyl, -(C3-C6)cycloalkyl, or -(4-8membered)heterocyclyl;or R8a and R9a, together with the carbon atoms to which they are attached, form (C3-C6)cycloalkyl, (4-8 membered)heterocyclyl, or (5-9 membered)heteroaryl, wherein the aforementioned group is optionally substituted with 1, 2, 3, 4, 5, 6, or 7 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, and -(C6-C10)aryl;or R8b and R9b, together with the carbon atoms to which they are attached, form (C3-C6)cycloalkyl, (4-8 membered)heterocyclyl, or (5-9 membered)heteroaryl, wherein the aforementioned group is optionally substituted with 1, 2, 3, 4, 5, 6, or 7 groups selected from hydrogen, halogen, -OH, -O-(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, -N[(C1-C4)alkyl]2, -(C3-C6)cycloalkyl, and -(C6-C10)aryl;preferably, R8a and R9a are absent, and R8b and R9b, together with the atoms to which they areattached, form, wherein * indicates the position of the attached atom.

17. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-16, wherein R10 is selected from -OH, or R10 and R9a, together with the atoms to which they are attached, form 5-membered nitrogen-containing heterocyclyl, wherein the 5-membered nitrogen-containing heterocyclyl is optionally substituted with 1, 2, 3, 4, or 5 groups selected from hydrogen, halogen, -OH, -(C1-C4)alkyl, -NH2, -NH(C1-C4)alkyl, and -N[(C1-C4)alkyl]2;preferably, R10 is -OH, or R10 and R9a, together with the atoms to which they are attached, form imidazolinyl, wherein the imidazolinyl is optionally substituted with 1, 2, or 3 groups selected from halogen, -OH, methyl, -NH2, -NH-methyl, and -N(methyl)2;preferably, R10 is -OH, or R10 and R9a, together with the atoms to which they are attached, formHN^)**, wherein * indicates the position of the attached atom;OHpreferably, R10 is -OH, preferably     .

18. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-17, wherein the drug group is selected from:a structure represented by formula I-A-1, II-A-1', III-A-1', IV-A-1, or V-A-1:wherein X, X1, X2, ring A, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, R12, m, n, M, W, U, Z, Y, L, Q, and T are defined as described in any one of claims 1-17;or a structure represented by formula I-A-5, II-A-5, III-A-5, IV-A-5, or V-A-5:I-A-5                              II-A-5III-A-5                  IV-A-5                       V-A-5wherein X, R1, ring A, R3, R5, R6, R7, R8b, R9a, R9b, R12, n, M, W, U, Z, Y, L, Q, and T are defined as described in any one of claims 1-17;or structures represented by formulas I-A-6 and I-A-7:I-A-6                                    I-A-7wherein R1, R31, R5, R6, R8b, R9a, R9b, and M are defined as described in any one of claims 1-17.

19. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-18, wherein the drug group is selected from the structures shown in Table A.

20. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, ordiastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-19, wherein the linking group is -Tr-L3-L2-L1-, and thelinking group and the drug group are linked to form astructure selected from a structurerepresented by formula I-B, II-B', III-B', IV-B, or V-B:I-B                                             II-B'III-B'                                IV-BV-Bwherein:X, X1, X2, ring A, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, R12, m, n, M, W, U, Z,Y, L, Q, and T are defined as described in any one of claims 1-19;Tr is absent, or Tr is any group;L3 is absent or is selected from a polypeptide fragment and a peptide fragment analog;L2 is absent or is selected from a linker fragment;L1 is a linking unit;the wavy line indicates linking to the ligand by a nitrogen atom or a carbon atom on the L1 group.

21. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-20, wherein:L1 is a linking unit;L2 is -(C(RL21)2)r-, wherein r is a natural number from 0 to 50;any C(RL21)2 unit in L2 may be independently replaced with the following structural unit: -Cy-, -C(=O)-, -NRL22-, -O-, -S-, -S(=O)-, -S(=O)2-, -P(RL22)-, -P(=O)(RL22)-, -C(=S)-, -C(=NRL22)-, -N=N-, -CH=N-, -N=CH-,or-Cy- is selected from -phenylene-, -(5-8 membered)heteroarylene-, -(4-10membered)heterocyclylene-, and -(C3-C10)cycloalkylene-, and -Cy- is unsubstituted, or each -Cy-is independently substituted with one or more RCx;RL21, RL22, and RCx are each independently selected from hydrogen, deuterium, halogen, nitro, -CN, -ORL2a, -SRL2a, -N(RL2a)2, -N+(RL2a)3, -C(=O)RL2a, -C(=O)ORL2a, -C(=O)-C(=O)RL2a, -C(=O)CH2C(=O)RL2a, -S(=O)RL2a, -S(=O)2RL2a, -C(=O)N(RL2a)2, -S(=O)2N(RL2a)2, -OC(=O)RL2a, -N(RL2a)S(=O)2RL2b, -N(RL2a)C(=O)RL2b, -(CH2)y-C(=O)-(N(Me)CH2C(=O))s-ORL2a, -(CH2)y-C(=O)-(N(Me)CH2C(=O))s-NHRL2a, -(CH2)y-C(=O)-(N(Me)CH2C(=O))s-N+(RL2a)3, -(CH2)y-NHC(=O)CH2(OCH2CH2)ORL2a, -(CH2)y-NH(C(=O)CH2(N(Me))s-RL2a, -(CH2)y-C(=O)NH-(CH2CH2O)s-RL2a,      -(CH2)y-NHC(=O)-(CH2CH2O)s-RL2a,      -(CH2CH2O)s-RL2a,      -(C(=O)CH2N(Me))s-RL2a, -C(=O)CH2(OCH2CH2)s-ORL2a, -C(=O)-(CH2CH2O)m-RL2a, -C(=O)-(CH2)y-C(=O)NH-(CH2CH2O)s-RL2a, -C(=O)-(CH2)y-NHC(=O)-(CH2CH2O)s-RL2a, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C3-C8)cycloalkyl, -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl, wherein the -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C3-C8)cycloalkyl, -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl are optionally substituted with one or more RL2a;s and y are each independently a natural number from 0 to 50;RL2a and RL2b are each independently selected from hydrogen, deuterium, halogen, nitro, -CN, -OH, -SH, -NH2, -N(Me)2, -C(=O)OH, -S(=O)2Me, -S(=O)2OH, -C(=O)NH2, -S(=O)2NH2, -(C1-C6)alkyl,        -(C2-C6)alkenyl,        -(C2-C6)alkynyl,        -(C3-C8)cycloalkyl,        -(4-10membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl;L3 is absent or is selected from an amino acid residue, a short peptide consisting of 2-10 aminoacid residues, -C(=O)-(C1-C6)alkylene-NH-,and any combination of the aforementionedgroups, wherein the amino acid residues are natural amino acid residues or non-natural amino acid residues, and L3 is optionally modified by one or more protecting groups; preferably, the protectinggroups are selected from a polyethylene glycol fragment and -OtBu, wherein the polyethylene glycol fragment is linked to L3 by the structural unit -NH-;Tr is absent or is selected from, and any combination of the aforementioned groups;RTr, RTr1, and RTr2 are each independently selected from hydrogen, deuterium, halogen, nitro, -CN, -OH, -NH2, -SH, -OC(=O)NH2, -C(=O)OH, -C(=O)NH2, -S(=O)2OH, -S(=O)2NH2, -CH2C(=O)-(N(Me)CH2C(=O))z-ORTra, -CH2C(=O)-(N(Me)CH2C(=O))z-NHRTra, -(CH2CH2O)z-RTra, -C(=O)NH-(CH2CH2O)z-RTra, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C3-C8)cycloalkyl, -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl, wherein the -(C1-C6)alkyl,      -(C2-C6)alkenyl,      -(C2-C6)alkynyl,      -(C3-C8)cycloalkyl,      -(4-10membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl are optionally substituted with one or more RTra;each RTra is independently hydrogen, deuterium, halogen, nitro, -CN, -OH, -NH2, -SH, -N(Me)2, -C(=O)OH, -C(=O)NH2, -S(=O)2OH, -S(=O)2NH2, -S(=O)2Me, -(C1-C6)alkyl, -(C2-C6)alkenyl, -(C2-C6)alkynyl, -(C3-C8)cycloalkyl, -(4-10 membered)heterocycloalkyl, -(C6-C10)aryl, and -(5-10 membered)heteroaryl;each z is independently a natural number from 0 to 50.

22. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-21, wherein:L1 is selected from carbonyl, -(C1-C8)alkylene-C(=O)-, -(4-8 membered)heterocyclylene-, -(5-10 membered)heteroarylene-, and -(C1-C8)alkylene-(5-10 membered)heteroarylene-, wherein the -(C1-C8)alkylene-C(=O)-, -(4-8 membered)heterocyclylene-, -(5-10 membered)heteroarylene-, and -(C1-C8)alkylene-(5-10 membered)heteroarylene- are optionally substituted with 1, 2, or 3 oxo, -(C1-C4)alkylene-, and -(C1-C4)alkyl groups;preferably, L1 is selected from carbonyl, -(C1-C4)alkylene-C(=O)-, -(5-6 membered)heterocyclylene-, -(5-6 membered)heteroarylene-, and -(C1-C4)alkylene-(5-6 membered)heteroarylene-, wherein the      -(C1-C4)alkylene-C(=O)-,       -(5-6membered)heterocyclylene-, -(5-6 membered)heteroarylene-, and -(C1-C4)alkylene-(5-6 membered)heteroarylene- are optionally substituted with 1, 2, or 3 oxo, -(C1-C4)alkylene-, and -(C1-C4)alkyl groups;preferably, L1 is selected from\\ \ *Z" N x , N—a. .V-Z>o      §— / —I *preferably, L1 is selected from "Z andwherein the * end is attached to L2.

23. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-22, wherein:L2 is -(C(RL21)2)r-, wherein r is a natural number from 0 to 10 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, or 9);any C(RL21)2 unit in L2 may be independently replaced with the following structural unit: -Cy-, -C(=O)-, -NRL22-, -O-, -S-, or -S(=O)-;-Cy- is selected from -phenylene-, -4-6 membered heterocyclylene-, and -(C3-C6)cycloalkylene-, and -Cy- is unsubstituted, or each -Cy- is independently substituted with 1, 2, 3, 4, 6, or 7 RCx;RL21, RL22, and RCx are each independently selected from hydrogen, deuterium, halogen, nitro, -CN, -ORL2a, -SRL2a, -N(RL2a)2, -C(=O)RL2a, -C(=O)ORL2a, -C(=O)-C(=O)RL2a, -C(=O)CH2C(=O)RL2a, -S(=O)RL2a, -S(=O)2RL2a, -C(=O)N(RL2a)2, -S(=O)2N(RL2a)2, -(CH2)2-C(=O)NH-(CH2CH2O)t-RL2a, -(C1-C6)alkyl, and -(C2-C6)alkenyl, wherein the -(C1-C6)alkyl and -(C2-C6)alkenyl are optionally substituted with 1, 2, 3, 4, 5, 6, or 7 RL2a;t is a natural number from 0 to 30;RL2a is selected from hydrogen, deuterium, fluorine, chlorine, bromine, iodine, nitro, -CN, -OH, -SH, -NH2, -N(Me)2, -C(=O)OH, -S(=O)2Me, -S(=O)2OH, -C(=O)2OH, -C(=O)NH2, -S(=O)2NH2, methyl, ethyl, and vinyl;preferably, L2 is -(C(RL21)2)r-, wherein r is 2, 3, 4, 5, 6, 7, 8, or 9;any C(RL21)2 unit in L2 may be independently replaced with the following structural unit: -Cy-, -C(=O)-, -NRL22-, -O-, -S-, or -S(=O)-;-Cy- is selected from cyclopropylene, cyclobutylene, cyclopentylene, azetidinylene, pyrrolidinylene, piperazinylene, or piperidinylene, and -Cy- is unsubstituted, or each -Cy- isindependently substituted with 1, 2, 3, 4, or 5 RCx; for example, -Cy- isI— nO—IH \ / —I or \'     ;RL21, RL22, and RCx are each independently selected from hydrogen, deuterium, fluorine, chlorine,bromine, iodine, nitro, -CN, -OH, -SH, -NH2, -C(=O)OH, -C(=O)NH, -(CH2)2-C(=O)NH-(CH2CH2O)11-CH3, methyl, ethyl, propyl, deuterated methyl, deuterated ethyl, halomethyl,haloethyl, methyl-OH, ethyl-OH, propyl-OH, vinyl-OH, vinyl, deuterated vinyl, and halovinyl;preferably, L2 is selected fromis selected frompreferably, L2and             , wherein the * end is attached to L3.

24. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvatethereof according to any one of claims 1-23, wherein:preferably,-L1-L2-   is selected from,, andH N,-L1-L2-isNO,,wherein theend is attached to L3.

25. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-24, wherein:L3 is selected from Val, D-Val, Phe, Lys, Leu, Ile, Gly, Ala, D-Ala, Cit, Asp, Asn, Glu, Gln, Arg, Ser, -Arg-Val-, -Arg-Leu-, -Val-Cit-, -Val-Ala-, -Val-Lys-, -Val-Lys(AC)-, -Phe-Lys-, -Phe-Lys(AC)-, -Leu-Lys-, -Leu-Lys(AC)-, -Ala-Ala-, -Ala-Lys-, -(D-Ala)-Ala-, -Gly-Glu-, -Gly-Asp-,-Gly-Asn-, -Val-Glu-, -Val-Asp-, -Asn-Asn-, -Asp-Asp-, -Asp-Glu-, -Ser-Val-, -Ser-Ala-, -Ser-Gly-, -Ser-Glu-, -Ser-Gln-, -Ser-Asp-, -Gly-Gln-, -Asn-Gly-, -Asn-Ala-, -Ala-Ala-Glu-, -Gly-Gly-Glu-, -Gly-Gly-Asp-, -Gly-Gly-Asn-, -Gly-Ala-Ala-, -Gly-Val-Ala-, -Gly-Val-Cit-, -Glu-Val-Cit-, -Ala-Ala-Ala-, -Ala-(D-Ala)-Ala-, -Ala-Ala-Asn-, -Ala-(D-Ala)-Asn-, -Ala-Ala-Asp-, -Val-Lys-Gly-, -(D-Val)-Leu-Lys-, -Gly-Gly-Arg-, -Gly-Gly-Gly-, -Lys-Ala-Asn-, -Gly-Phe-Gly-, -Gly-Gly-Phe-, -Asn-Pro-Val-, -Ala-Lys-Gly-, -Gly-Lys-Gly-, -Gly-Gly-Gly-Gly-, -Gly-Gly-Phe-Gly-,-Gly-Gly-Glu-Gly-, -Lys-Ala-Ala-Asn-, -Lys-Ala-Ala-Asp-, -Ala-Ala-Pro-Val-, -Ala-Ala-Pro-Nva-,, -C(=O)-(C1-C4)alkylene-NH-, and any combination of theaforementioned groups, wherein Asp and Glu are each independently and optionally modified by -(CH2CH2O)t-RL3, wherein -(CH2CH2O)t-RL3 is linked to Asp or Glu by the structural unit -NH-, RL3 is -(C1-C4)alkyl, and t is an integer from 6 to 30 (e.g., 8, 9, 10, 11, 12, 13, 14, 15, 20, 21, 22, 23, 24, or 25);preferably, L3 is selected from -Val-Cit-, -Arg-Val-, -Ala-Ala-, -Val-Ala-, -Gly-Glu-, -Ser-Val-, -Ser-Ala-, -Ser-Gly-, -Ser-Glu-, -Ser-Gln-, -Ser-Asp-, -Gly-Gln-, -Asn-Gly-, -Asn-Ala-, -Ala-Ala-Glu-, -Gly-Ala-Ala-, -Gly-Gly-Glu-, -Gly-Gly-Phe-Gly-, -Ala-Ala-Glu(NH-(CH2CH2O)t-RL3)-, and -C(=O)-CH2CH2-NH-, wherein RL3 is -(C1-C4)alkyl, and t is an integer from 6 to 30; an example is -Ala-Ala-Glu(NH-(CH2CH2O)11-CH3)- or -Ala-Ala-Glu(NH-(CH2CH2O)24-CH3)-;preferably, L3 is selected from -Val-Cit-*, *-Ala-Ala-, -Val-Ala-*, *-Gly-Glu-, *-Ser-Val-, *-Ser-Ala-, *-Ser-Gly-, *-Ser-Glu-, *-Ser-Gln-, *-Ser-Asp-, -Gly-Gln-*, *-Gly-Gln-, *-Asn-Gly-, *-Asn-Ala-, *-Gly-Ala-Ala-, *-Gly-Gly-Glu-, -Gly-Gly-Phe-Gly-*, *Ala-Ala-C(=O)-CH[CH2CH2-0C(=O)-NH-(CH2CH2O)11-CH3]-NH-, and           H , wherein the * end is attached to Tr.

26. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvatethereof according to any one of claims 1-25, wherein:Tr is absent or is selected fromandRTr, RTr1, and RTr2 are each independently selected from hydrogen, deuterium, halogen, nitro, -CN, -OH, -NH2, -SH, -OC(=O)NH2, -C(=O)OH, -C(=O)NH2, -S(=O)2OH, -S(=O)2NH2, -(CH2CH2O)z-RTra, -C(=O)NH-(CH2CH2O)z-RTra, gluconolactone, glucuronic acid, -(C1-C4)alkyl, and -(C2-C4)alkenyl, wherein the -(C1-C4)alkyl and -(C2-C4)alkenyl are optionally substituted with 1, 2, 3, 4, or 5 RTra;each RTra is independently hydrogen, deuterium, halogen, nitro, -CN, -OH, -NH2, -SH, -N(Me)2, -C(=O)OH, -C(=O)NH2, -S(=O)2OH, -S(=O)2NH2, -S(=O)2Me, -(C1-C4)alkyl, or -(C2-C4)alkenyl; each z is independently an integer from 6 to 30;preferably, RTr, RTr1, and RTr2 are each independently selected from hydrogen, deuterium, fluorine, chlorine, bromine, iodine, nitro, -CN, -OH, -NH2, -SH, -OC(=O)NH2, -C(=O)OH, -C(=O)NH2, -S(=O)2OH, -S(=O)2NH2, -(CH2CH2O)z-RTra, -C(=O)NH-(CH2CH2O)z-RTra, gluconolactone, glucuronic acid, methyl, ethyl, -ethylene-OH, and -CH2-COOH;each RTra is independently hydrogen, deuterium, fluorine, chlorine, bromine, iodine, -CN, -OH, -NH2, -SH, -N(Me)2, -C(=O)OH, -C(=O)NH2, methyl, or ethyl;each z is independently an integer from 6 to 30 (e.g., 8, 9, 10, 11, 12, 13, 14, 15, 20, 21, 22, 23, 24, or 25);QHpreferably, RTr is selected from hydrogen, -CH2-COOH, andpreferably, Tr is absent or is selected fromQHselectedpreferably, Tr is absent or isOHfromwherein the *27. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvatethereof according to any one of claims 1-26, wherein:from28. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-27, wherein the linking group and the drug group are linked to form a structure selected from:a structure represented by formula I-B-1, II-B-1', III-B-1', IV-B-1, or V-B-1:i3 -LlK2V-B-1wherein X, X1, X2, ring A, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, R12, m, n, M, W, U, Z, Y, L, Q, T, Tr, L1, L2, and L3 are defined as described in any one of claims 1-27;or a structure represented by formula I-B-5, II-B-5, III-B-5, IV-B-5, or V-B-5:I-B-5II-B-5III-B-5L1'L"L3V-B-5wherein X, R1, ring A, R3, R5, R6, R7, R8b, R9a, R9b, R12, n, M, W, U, Z, Y, L, Q, T, Tr, L1, L2, and L3 are defined as described in any one of claims 1-27;or structures represented by formulas I-B-6 and I-B-7:I-B-6I-B-7wherein R1, R31, R5, R6, R8b, R9a, R9b, M, Tr, L1, L2, and L3 are defined as described in any one of claims 1-27.

29. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-28, wherein the linking group and the drug group are linked to form a structure selected from the structures shown in Table B.

30. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvatethereof according to any one of claims 1-29, wherein the ligand-drug conjugate is selected from acompound represented by formula I-C, II-C', III-C', IV-C, or V-C:I-C                                        II-C'III-C'                                        IV-CV-Cwherein:X, X1, X2, ring A, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, R12, m, n, M, W, U, Z, Y, L, Q, T, Tr, L1, L2, and L3 are defined as described in any one of claims 1-29;Ab is a ligand that binds to a target;k is a drug loading and is an integer or a decimal from 1 to 16.

31. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-30, wherein Ab is conjugated to L1 by an S atom;preferably, Ab is a polypeptide, or an antibody or an antigen-binding fragment thereof, particularly an antibody or an antigen-binding fragment thereof, capable of specifically binding to a target;preferably, the antibody is selected from one or more of the following:(1) a fully human antibody, a humanized antibody, a murine antibody, and a chimeric antibody, (2) a probody,(3) a bispecific antibody and a multispecific antibody,(4) a monoclonal antibody and a polyclonal antibody, and(5) an IgG antibody;preferably, the antigen-binding fragment is selected from an antigen-binding fragment of a Fab, a Fab', a F(ab')2, an Fv, an scFv, an Fd, a dAb, a VHH, and a complementarity-determining region (CDR) fragment;preferably, Ab is a monoclonal antibody, particularly a monoclonal antibody that takes sulfhydryl as a conjugation site, or a monoclonal antibody that has undergone site-directed mutagenesis or modification and takes sulfhydryl as a conjugation site;preferably, Ab targets an antigen selected from the following group: HER2, HER3, B7H3, B7H4, DLL3, TROP2, Claudin18.2, CD30, CD33, CD70, EGFR, GPC-3, ADAM9, BCMA, CEACAM5, and c-met;preferably, Ab is selected from antibodies and antigen-binding fragments thereof against HER2, HER3, B7H3, TROP2, Claudin18.2, CD30, CD33, CD70, GPC-3, ADAM9, BCMA, CEACAM5, and c-met;preferably, Ab is selected from tusamitamab, DB1001, DB1002, DB1003, DB1004, DB1005, cetuximab, and panitumumab, and biosimilars of the antibodies and antigen-binding fragments thereof;preferably, Ab is selected from tusamitamab, DB1001, DB1002, DB1003, DB1004, and DB1005, andantigen-binding fragments of the antibodies;preferably, Ab comprises the sequences of a CDR1, a CDR2, and a CDR3 contained in a heavy chain set forth in SEQ ID NO: 1, and / or the sequences of a CDR1, a CDR2, and a CDR3 contained in a light chain set forth in SEQ ID NO: 2; or Ab comprises the sequences of a CDR1, a CDR2, and a CDR3 contained in a heavy chain set forth in SEQ ID NO: 3, and / or the sequences of a CDR1, a CDR2, and a CDR3 contained in a light chain set forth in SEQ ID NO: 4; or Ab comprises the sequences of a CDR1, a CDR2, and a CDR3 contained in a heavy chain set forth in SEQ ID NO: 5, and / or the sequences of a CDR1, a CDR2, and a CDR3 contained in a light chain set forth in SEQ ID NO: 6; or Ab comprises the sequences of a CDR1, a CDR2, and a CDR3 contained in a heavy chain set forth in SEQ ID NO: 25, and / or the sequences of a CDR1, a CDR2, and a CDR3 contained in a light chain set forth in SEQ ID NO: 26; or Ab comprises the sequences of a CDR1, a CDR2, and a CDR3 contained in a heavy chain set forth in SEQ ID NO: 35, and / or the sequences of a CDR1, a CDR2, and a CDR3 contained in a light chain set forth in SEQ ID NO: 36; or Ab comprises the sequences of a CDR1, a CDR2, and a CDR3 contained in a heavy chain set forth inSEQ ID NO: 15, and / or the sequences of a CDR1, a CDR2, and a CDR3 contained in a light chain set forth in SEQ ID NO: 16;preferably, Ab comprises a heavy chain variable region CDR1 set forth in SEQ ID NO: 7, a heavy chain variable region CDR2 set forth in SEQ ID NO: 8, and a heavy chain variable region CDR3 set forth in SEQ ID NO: 9, and / or a light chain variable region CDR1 set forth in SEQ ID NO: 10, a light chain variable region CDR2 set forth in SEQ ID NO: 11, and a light chain variable region CDR3 set forth in SEQ ID NO: 12; or, a heavy chain variable region CDR1 set forth in SEQ ID NO: 17, a heavy chain variable region CDR2 set forth in SEQ ID NO: 18, and a heavy chain variable region CDR3 set forth in SEQ ID NO: 19, and / or a light chain variable region CDR1 set forth in SEQ ID NO: 20, a light chain variable region CDR2 set forth in SEQ ID NO: 21, and a light chain variable region CDR3 set forth in SEQ ID NO: 22; or, a heavy chain variable region CDR1 set forth in SEQ ID NO: 27, a heavy chain variable region CDR2 set forth in SEQ ID NO: 28, and a heavy chain variable region CDR3 set forth in SEQ ID NO: 29, and / or a light chain variable region CDR1 set forth in SEQ ID NO: 30, a light chain variable region CDR2 set forth in SEQ ID NO: 31, and a light chain variable region CDR3 set forth in SEQ ID NO: 32; or, a heavy chain variable region CDR1 set forth in SEQ ID NO: 37, a heavy chain variable region CDR2 set forth in SEQ ID NO: 38, and a heavy chain variable region CDR3 set forth in SEQ ID NO: 39, and / or a light chain variable region CDR1 set forth in SEQ ID NO: 40, a light chain variable region CDR2 set forth in SEQ ID NO: 41, and a light chain variable region CDR3 set forth in SEQ ID NO: 42; or, a heavy chain variable region CDR1 set forth in SEQ ID NO: 45, a heavy chain variable region CDR2 set forth in SEQ ID NO: 46, and a heavy chain variable region CDR3 set forth in SEQ ID NO: 47, and / or a light chain variable region CDR1 set forth in SEQ ID NO: 48, a light chain variable region CDR2 set forth in SEQ ID NO: 49, and a light chain variable region CDR3 set forth in SEQ ID NO: 50; or, a heavy chain variable region CDR1 set forth in SEQ ID NO: 53, a heavy chain variable region CDR2 set forth in SEQ ID NO: 54, and a heavy chain variable region CDR3 set forth in SEQ ID NO: 55, and / or a light chain variable region CDR1 set forth in SEQ ID NO: 56, a light chain variable region CDR2 set forth in SEQ ID NO: 57, and a light chain variable region CDR3 set forth in SEQ ID NO: 58;preferably, Ab comprises the sequence of a heavy chain variable region contained in a heavy chain set forth in SEQ ID NO: 1, and / or the sequence of a light chain variable region contained in a light chain set forth in SEQ ID NO: 2; or Ab comprises the sequence of a heavy chain variable region contained in a heavy chain set forth in SEQ ID NO: 3, and / or the sequence of a light chain variable region contained in a light chain set forth in SEQ ID NO: 4; or Ab comprises the sequence of a heavy chain variable region contained in a heavy chain set forth in SEQ ID NO: 5, and / or the sequence of a light chain variable region contained in a light chain set forth in SEQ ID NO: 6; or Ab comprises the sequence of a heavy chain variable region contained in a heavy chain set forthin SEQ ID NO: 25, and / or the sequence of a light chain variable region contained in a light chain set forth in SEQ ID NO: 26; or Ab comprises the sequence of a heavy chain variable region contained in a heavy chain set forth in SEQ ID NO: 35, and / or the sequence of a light chain variable region contained in a light chain set forth in SEQ ID NO: 36; or Ab comprises the sequence of a heavy chain variable region contained in a heavy chain set forth in SEQ ID NO: 15, and / or the sequence of a light chain variable region contained in a light chain set forth in SEQ ID NO: 16; preferably, Ab comprises the sequence of a heavy chain variable region set forth in SEQ ID NO: 14 and / or the sequence of a light chain variable region set forth in SEQ ID NO: 13; or Ab comprises the sequence of a heavy chain variable region set forth in SEQ ID NO: 24 and / or the sequence of a light chain variable region set forth in SEQ ID NO: 23; or Ab comprises the sequence of a heavy chain variable region set forth in SEQ ID NO: 34 and / or the sequence of a light chain variable region set forth in SEQ ID NO: 33; or Ab comprises the sequence of a heavy chain variable region set forth in SEQ ID NO: 44 and / or the sequence of a light chain variable region set forth in SEQ ID NO: 43; or Ab comprises the sequence of a heavy chain variable region set forth in SEQ ID NO: 52 and / or the sequence of a light chain variable region set forth in SEQ ID NO: 51; or Ab comprises the sequence of a heavy chain variable region set forth in SEQ ID NO: 60 and / or the sequence of a light chain variable region set forth in SEQ ID NO: 59;preferably, the amino acid sequence of a heavy chain of Ab is set forth in SEQ ID NO: 1, and the amino acid sequence of a light chain of Ab is set forth in SEQ ID NO: 2; or the amino acid sequence of a heavy chain of Ab is set forth in SEQ ID NO: 3, and the amino acid sequence of a light chain of Ab is set forth in SEQ ID NO: 4; or the amino acid sequence of a heavy chain of Ab is set forth in SEQ ID NO: 5, and the amino acid sequence of a light chain of Ab is set forth in SEQ ID NO: 6; or the amino acid sequence of a heavy chain of Ab is set forth in SEQ ID NO: 25, and the amino acid sequence of a light chain of Ab is set forth in SEQ ID NO: 26; or the amino acid sequence of a heavy chain of Ab is set forth in SEQ ID NO: 35, and the amino acid sequence of a light chain of Ab is set forth in SEQ ID NO: 36; or the amino acid sequence of a heavy chain of Ab is set forth in SEQ ID NO: 15, and the amino acid sequence of a light chain of Ab is set forth in SEQ ID NO: 16;preferably, Ab is an anti-CEACAM5 antibody or an antigen-binding fragment thereof, e.g., tusamitamab or an antigen-binding fragment thereof or a variant thereof;preferably, Ab comprises a heavy chain and a light chain of the anti-CEACAM5 antibody or the antigen-binding fragment thereof, wherein the amino acid sequence of the heavy chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 1 or is set forth in SEQ ID NO: 1, and the amino acid sequence of the light chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 2 or is set forth in SEQ ID NO: 2; orpreferably, Ab is an anti-HER3 antibody or an antigen-binding fragment thereof, e.g., DB1001 or an antigen-binding fragment thereof or a variant thereof;preferably, Ab comprises a heavy chain and a light chain of the anti-HER3 antibody or the antigenbinding fragment thereof, wherein the amino acid sequence of the heavy chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 3 or is set forth in SEQ ID NO: 3, and the amino acid sequence of the light chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 4 or is set forth in SEQ ID NO: 4; orpreferably, Ab is an anti-GPC-3 antibody or an antigen-binding fragment thereof, e.g., DB1002 or an antigen-binding fragment thereof or a variant thereof;preferably, Ab comprises a heavy chain and a light chain of the anti-GPC-3 antibody or the antigenbinding fragment thereof, wherein the amino acid sequence of the heavy chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 5 or is set forth in SEQ ID NO: 5, and the amino acid sequence of the light chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 6 or is set forth in SEQ ID NO: 6; orpreferably, Ab is an anti-ADAM9 antibody or an antigen-binding fragment thereof, e.g., DB1003 or an antigen-binding fragment thereof or a variant thereof;preferably, Ab comprises a heavy chain and a light chain of the anti-ADAM9 antibody or the antigen-binding fragment thereof, wherein the amino acid sequence of the heavy chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 25 or is set forth in SEQ ID NO: 25, and the amino acid sequence of the light chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 26 or is set forth in SEQ ID NO: 26; orpreferably, Ab is an anti-BCMA antibody or an antigen-binding fragment thereof, e.g., DB1004 or an antigen-binding fragment thereof or a variant thereof;preferably, Ab comprises a heavy chain and a light chain of the anti-BCMA antibody or the antigen-binding fragment thereof, wherein the amino acid sequence of the heavy chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 35 or is set forth in SEQ ID NO: 35, and the amino acid sequence of the light chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 36 or is set forth in SEQ ID NO: 36; orpreferably, Ab is an anti-c-met antibody or an antigen-binding fragment thereof, e.g., DB1005 or an antigen-binding fragment thereof or a variant thereof;preferably, Ab comprises a heavy chain and a light chain of the anti-c-met antibody or the antigenbinding fragment thereof, wherein the amino acid sequence of the heavy chain is a sequence havingat least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 15 or is set forth in SEQ ID NO: 15, and the amino acid sequence of the light chain is a sequence having at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 16 or is set forth in SEQ ID NO: 16.

32. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-31, wherein k is selected from integers or decimals from 1 to 10, preferably integers or decimals from 2 to 8, e.g., integers or decimals from 4 to 8 (e.g., about 4, about 4.5, about 5, about 5.5, about 6, about 6.5, about 7, about 7.5, or about 8), e.g., integers or decimals from 6 to 8 (e.g., about 6.1, about 6.3, about 6.5, about 6.7, about 6.9, about 7.1, about 7.3, about 7.5, about 7.7, or about 8), e.g., integers or decimals from 7 to 8 (e.g., about 7.1, about 7.2, about 7.3, about 7.4, about 7.5, about 7.6, about 7.7, about 7.8, about 7.9, or about 8).

33. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-32, wherein the ligand-drug conjugate is selected from: a compound represented by formula I-C-1, II-C-1', III-C-1', IV-C-1, or V-C-1:AbkkV-C-1wherein X, X1, X2, ring A, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, R12, m, n, M, W, U, Z, Y, L, Q, T, Tr, L1, L2, L3, Ab, and k are defined as described in any one of claims 1-32;or a compound represented by formula I-C-5, II-C-5, III-C-5, IV-C-5, or V-C-5:V-C-5wherein X, R1, ring A, R3, R5, R6, R7, R8b, R9a, R9b, R12, n, M, W, U, Z, Y, L, Q, T, Tr, L1, L2, L3,Ab, and k are defined as described in any one of claims 1-32;or compounds represented by formulas I-C-6 and I-C-7:I-C-6I-C-7wherein R1, R31, R5, R6, R8b, R9a, R9b, M, Tr, L1, L2, L3, Ab, and k are defined as described in any one of claims 1-32.

34. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-33, wherein the ligand-drug conjugate is selected from the structures shown in Table C.

35. The ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-34, wherein the ligand-drug conjugate is selected from the structures shown in Table E.

36. A mixture of ligand-drug conjugates, comprising or consisting of the ligand-drug conjugate, the tautomer thereof, the enantiomer thereof, the diastereoisomer thereof, the pharmaceutically acceptable salt thereof, or the solvate thereof according to any one of claims 1-35, wherein the ligand-drug conjugate has one, two, or more k values.

37. A compound or a racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or a mixture thereof, or a pharmaceutically acceptable salt or solvate thereof, wherein the compound is selected from a structure represented by formula I-D, II-D', III-D', IV-D, or V-D:V-Dwherein:X, X1, X2, ring A, ring B, ring C, R3, R4, R5, R6, R7, R8a, R8b, R9a, R9b, R10, R12, m, n, M, W, U, Z,Y, L, Q, T, Tr, L2, and L3 are defined as described in any one of claims 1-28;L1a is a linking unit.

38. The compound or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to claim 37, wherein:L1a is selected from -C(=O)-(C1-C8)alkyl, -C(=O)O-(4-8 membered)heterocyclyl, -C(=O)O-(C6-C10)aryl, (4-8 membered)heterocyclyl, and (5-10 membered)heteroaryl, wherein the -C(=O)-(C1-C8)alkyl, -C(=O)O-(4-8 membered)heterocyclyl, -C(=O)O-(C6-C10 membered)aryl, (4-8 membered)heterocyclyl, and (5-10 membered)heteroaryl are optionally substituted with 1, 2, 3, 4, or 5 oxo, halogen, =CH2, -(C2-C4)alkenyl, -S-CH2-phenyl, -S(=O)2-(C1-C4)alkyl, -O-S(=O)2-phenyl-(C1-C4)alkyl, and -(C1-C4)alkyl groups;L1a is selected from -C(=O)-(C1-C4)alkyl, -C(=O)O-(5-6 membered)heterocyclyl, -C(=O)O-phenyl, (5-6 membered)heterocyclyl, and (5-6 membered)heteroaryl, wherein the -C(=O)-(C1-C4)alkyl, -C(=O)O-(5-6 membered)heterocyclyl, -C(=O)O-phenyl, (5-6 membered)heterocyclyl, and (5-6 membered)heteroaryl are optionally substituted with 1, 2, 3, 4, or 5 oxo, fluorine, bromine, =CH2, vinyl, -S-CH2-phenyl, -S(=O)2CH3, -O-S(=O)2-phenyl-CH3, and methyl groups;preferably,L1a isselected frompreferably, L1a is selected fromand39. The compound or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to claim 37 or 38, wherein the compound is selected from the structures shown in Table D.

40. Use of the compound or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 37-39 in the manufacture of the ligand-drug conjugate according to any one of claims 1-36.

41. A pharmaceutical composition, comprising at least one of the ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-35, or at least one of the mixture of ligand-drug conjugates according to claim 36, or at least one of the compound or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 37-39, and one or more pharmaceutically acceptable carriers and / or excipients.

42. Use of the ligand-drug conjugate or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof, or the mixture thereof, or the pharmaceutically acceptable salt or solvate thereof according to any one of claims 1-35, or the mixture of ligand-drug conjugates according to claim 36, or the compound or the racemic mixture, tautomer, stereoisomer, enantiomer, or diastereoisomer thereof or the mixture thereof according to any one of claims 3739, or the pharmaceutical composition according to claim 41 in the manufacture of a medicament for treating and / or preventing a disease or disorder or reducing the severity of the disease or disorder, wherein the disease or disorder is a tumor or cancer;preferably, the tumor or cancer is selected from leukemia, malignant lymphoma, multiple myeloma, gastric cancer, colorectal cancer, pancreatic cancer, colon cancer, breast cancer, ovarian cancer, liver cancer, and lung cancer.

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