In this study, participants with high-risk non-muscle-invasive bladder cancer (NMIBC) unresponsive to Bacillus Calmette Guerin (BCG) therapy and who are considered ineligible for or have refused to undergo radical cystectomy, will receive pembrolizumab therapy or pembrolizumab in combination with other investigational agents. The primary study hypothesis is that treatment with pembrolizumab will result in a … Continued