The purpose of this study is to compare event-free survival (EFS) in participants with Bacillus Calmette-Guerin (BCG)-naive high-risk non-muscle invasive bladder cancer (HR-NMIBC), including high-grade papillary Ta, any T1, or carcinoma in situ (CIS), between TAR-200 plus cetrelimab (Group A) and TAR-200 alone (Group C) versus intravesical BCG (Group B).