About 50% of patients with locally advanced or metastatic urothelial carcinoma are not eligible for first-line treatment with standard-of-care combination cisplatin-based chemotherapy due to impaired renal function, poor performance status, and other comorbidities. In the limited number of patients treated with PD-1/PD-L1 inhibitors, outcomes remain poor, with a median overall survival of 10.4 months.