A Study of TAR-200 in Combination With Cetrelimab, TAR-200 Alone, or Cetrelimab Alone in Participants With Non-Muscle Invasive Bladder Cancer (NMIBC) Unresponsive to Intravesical Bacillus Calmette-Guérin Who Are Ineligible for or Elected Not to Undergo Radical Cystectomy

Prior treatment

• Must not have had urothelial carcinoma or histological variant at any site outside of the urinary bladder. Ta/T1/CIS of the upper urinary tract (including renal pelvis and ureter) is allowable if treated with complete nephroureterectomy more than 24 months prior to randomization
• Received a live virus vaccine within 30 days prior to the initiation of study treatment. Inactivated (non-live or non-replicating) vaccines approved or authorized for emergency use (for example, COVID-19) by local health authorities are allowed
• Prior therapy with an anti-programmed-cell death 1 (PD-1), anti-PD-ligand 2 (L2) agent, or with an agent directed to another co-inhibitory T-cell receptor

Other illness

• Presence or history of histologically confirmed, muscle-invasive, locally advanced, nonresectable, or metastatic urothelial carcinoma (that is, T2, T3, T4, and/or Stage IV)
• Active hepatitis B or C infection (for example, participants with history of hepatitis C infection but undetectable hepatitis C virus polymerase chain reaction (PCR) test and participants with history of hepatitis B infection with positive hepatitis B surface antigen (HBsAg) antibody and undetectable PCR are allowed)

• Histologically confirmed diagnosis of persistent or recurrent high-risk non-muscle invasive bladder cancer (HR-NMIBC), (carcinoma in situ \[CIS\] or tumor in situ \[Tis\]), with or without papillary disease (T1, high-grade Ta) or papillary disease only (high-grade Ta or any T1 and absence of CIS), within 12 months of completion of the last dose of Bacillus Calmette-Guerin (BCG) therapy, in participants who have received adequate BCG. Mixed histology tumors are allowed if urothelial differentiation (transitional cell histology) is predominant. However, the presence of neuroendocrine, micropapillary, signet ring cell, plasmacytoid, or sarcomatoid features will make a participant ineligible. For participants with lamina propria invasion (T1) on the screening biopsy/ transurethral resection of bladder tumor (TURBT), muscularis propria must be present in order to rule out Muscle Invasive Bladder Cancer (MIBC)
• All visible papillary disease must be fully resected (absent) prior to randomization (residual CIS is acceptable for participants eligible for Cohorts 1, 2, and 3 only) and documented in the electronic case report form (eCRF) at screening cystoscopy. For participants with papillary disease only (Cohort 4), local urine cytology at screening must be negative or atypical (for High-Grade Urothelial Carcinoma \[HGUC\])
• Participants must be ineligible for or have elected not to undergo radical cystectomy
• BCG-unresponsive high-risk NMIBC after treatment with adequate BCG therapy defined as a minimum of 5 of 6 full doses of an induction course (adequate induction) plus 2 of 3 doses of a maintenance course, or at least 2 of 6 doses of a second induction course
• Eastern Cooperative Oncology Group (ECOG) performance status Grade 0, 1, or 2