Clinical Summary: Design/Population: Phase 3 AMBASSADOR trial assessing health-related quality of life in 560 patients with high-risk muscle-invasive urothelial carcinoma randomized to adjuvant pembrolizumab or observation after radical surgery. Key Outcomes: At 12 months, no statistically significant or clinically meaningful differences in patient-reported outcomes were observed between treatment arms across EQ-5D-5L, EORTC QLQ-C30, and BLM30 measures.