A Study of Nivolumab Plus Bempegaldesleukin (Bempeg/NKTR-214) vs Nivolumab Alone vs Standard of Care in Participants With Bladder Cancer That May Have Invaded The Muscle Wall of the Bladder and Who Cannot Get Cisplatin, A Type of Medicine Given To Treat Bladder Cancer

Inclusion Criteria:

Urothelial carcinoma (UC) of the bladder, clinical stage T2-T4aN0, M0 or T1-T4aN1, M0, diagnosed at transurethral resection of bladder tumor (TURBT)
Must be deemed eligible for Radical Cystectomy (RC) by urologist, and must agree to undergo RC. For arms A and B, participants must agree to undergo RC after completion of neoadjuvant therapy.
Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1

Cisplatin-ineligible participants will be defined by any one of the following criteria:

i) Impaired renal function (glomerular filtration rate [GFR] ≥ 30 but < 60 mL/min) ii) GFR should be assessed by direct measurement (ie, creatinine clearance) or, if not available, by calculation from serum/plasma creatinine (Cockcroft-Gault formula) iii) Common Terminology Criteria for Adverse Events (CTCAE) version 5, ≥ Grade 2 hearing loss (assessed per local SOC).

iv) CTCAE version 5, ≥ Grade 2 peripheral neuropathy.

Documented Left Ventricular Ejection Fraction (LVEF) more than 45%

Exclusion Criteria:

Clinical evidence of ≥ N2 or metastatic bladder cancer
Prior systemic therapy, radiation therapy, or surgery for bladder cancer other than TURBT or biopsies is not permitted. Prior Bacillus Calmette-Guerin (BCG) or other intravesicular treatment of non-muscle invasive bladder cancer (NMIBC) is permitted if completed at least 6 weeks prior to initiating study treatment.
Evidence of urothelial carcinoma (UC) in upper urinary tracts (ureters or renal pelvis) or history of previous MIBC
History of pulmonary embolism (PE), deep vein thrombosis (DVT), or prior clinically significant venous or non-CVA(cerebrovascular accident)/TIA (Transient ischemic attack) arterial thromboembolic event
Known cardiovascular history, including unstable or deteriorating cardiac disease within the previous 12 months (including unstable angina or myocardial infarction, congestive heart failure or uncontrolled clinically significant arrhythmias)

Other protocol-defined inclusion/exclusion criteria apply