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