The present invention provides diagnostic methods, therapeutic methods, and compositions for the treatment of cancer. The compositions and methods described herein can be used, for example, to determine the propensity of a patient to benefit from treatment with a PD-L1 axis binding antagonist and to treat such patients accordingly. Using the compositions and methods of the disclosure, a patient, such as a human cancer patient, may be determined to be likely to benefit from treatment with a PD-L1 axis binding antagonist if the patient exhibits an elevated pre-treatment expression level of one or more of CST7, NKG7, GZMH, MT-ND4, HLA-H, CCL5, CD8A, CMC1, CD8B, HCST, MT-CYB, MT-ND4L, KLRG1, MT-CO2, MT-ATP6, PLEK, CTSW, HLA-C, LYAR, LITAF, GZMB, KLRD1, FGFBP2, KLRC4-KLRK1, KLRK1, B2M, GZMA, ID2, CX3CR1, PRSS23, GNLY, PRF1, and PATL2. Exemplary PD-L1 axis binding antagonists that may be used in conjunction with the compositions and methods of the disclosure are PD-L1 binding antagonists, such as anti-PD-L1 antibodies and antigen-binding fragments thereof, including atezolizumab, as well as PD-1 binding antagonists, such as anti-PD-1 antibodies and antigen-binding fragments thereof.