A Study of TAR-200 in Combination With Cetrelimab Versus Concurrent Chemoradiotherapy in Participants With Muscle-invasive Bladder Cancer (MIBC) of the Bladder

Inclusion Criteria: * Ineligible for or have elected not to undergo radical cystectomy * All adverse events associated with any prior surgery and/or intravesical therapy must have resolved to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 Grade less than (\<) 2 prior to randomization * Eastern Cooperative Oncology Group (ECOG) performance status Grade 0, 1, or 2 * Thyroid function tests are within the normal range per investigator assessment (or stable on hormone supplementation). Investigators may consult an endocrinologist for participant eligibility assessment in the case of equivocal or marginal test results * Adequate bone marrow, liver, and renal function: Bone marrow function (without the support of cytokines or erythropoiesis-stimulating agent in preceding two weeks): Absolute neutrophil count (ANC) greater than or equal to (\>=) 1,500/cubic millimeters (mm\^3); Platelet count \>=80,000/mm\^3; Hemoglobin \>=9.0 grams per deciliter (g/dL); Liver function: (Total bilirubin less than or equal to (\<=) 1.5 \* upper limit of normal (ULN) or direct bilirubin \<= ULN for participants with total bilirubin levels greater than (\>)1.5\*ULN (except participants with Gilbert's Syndrome, who must have a total bilirubin \< 3.0 mg/dL), and Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) less than or equal to (\<=) 2.5\* institutional ULN); Renal function: Creatinine clearance \>=30 mL/min using the Cockcroft-Gault formula. 24-hour creatinine …