To our knowledge, this is the first study to evaluate the efficacy of PD1/L1 blockade in the first-line setting for platinum-ineligible (i.e. ineligible for both cisplatin and carboplatin) advanced urothelial carcinoma (aUC) in the real world. This is a multicenter retrospective study of 79 patients with aUC who were considered platinum-ineligible at the discretion of the treating medical oncologist due to: 1) those with both renal dysfunction (CrCl<60 ml/min) and poor ECOG performance status [PS]=2, 2) CrCl <30 ml/minute or 3) ECOG-PS=3, 4) elderly or 5) severe comorbidities that were deemed prohibitive for platinum-based chemotherapy. A recent presentation (Gupta et al) reported consensus criteria for platinum-eligibility, which are also arbitrary but similar to the criteria that we employed.