Provided are methods of treating bladder cancer (e.g., urothelial carcinoma, UC) in a subject having bladder cancer, e.g., UC, with an effective dose regimen of an anti-PD-L1 antibody, e.g., durvalumab, or an antigen binding fragment thereof. Also provided are methods in which an anti-PD-L1 antibody is used in combination with another immunotherapeutic agent, e.g., tremelimumab to treat a bladder cancer, e.g., UC, in a subject having bladder cancer. In some cases, the subject undergoing treatment is identified as having a bladder cancer or tumor that is PD-L1-low/neg, or PD-L1-high. Methods are also provided in which anti-PD-L1 antibody treatment of bladder cancer is used following a standard of care or first-line therapy in subjects who have progressed following such therapies or who have relapsed after a prior treatment regimen.
