This is a study that will test how an experimental drug (enfortumab vedotin) affects patients with cancer of the urinary system (urothelial cancer). This type of cancer includes cancer of the bladder, renal pelvis, ureter or urethra that has spread to nearby tissues or to other areas of the body. This clinical trial will enroll patients who were previously treated with a kind of anticancer drug called an immune checkpoint inhibitor (CPI). Some CPIs have been approved for the treatment of urothelial cancer. This study will test if the cancer shrinks with treatment. This study will also look at the side effects of the drug. A side effect is a response to a drug that is not part of the treatment effect.