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

Pathologic Complete Response (pCR) Rate - Nivolumab Compared to Standard of Care

Pathologic Complete Response (pCR) is defined as the percentage of randomized participants with absence of any cancer in pathology specimens after radical cystectomy, based on blinded independent pathology review (BIPR). Participants who do not undertake surgery will be counted as non-pCR.

Time frame: From time of radical cystectomy up to 100 days after last treatment (up to approximately 17 months)

Event Free Survival (EFS) - Nivolumab Compared to Standard of Care

Event Free Survival (EFS) is defined as the time from randomization to any of the following events: progression of disease that precludes surgery, local or distant recurrence based on blinded independent committee review (BICR) assessments, or death due to any cause. Participants who did not have an EFS event will be censored on the date of their last evaluable tumor assessment (imaging or biopsy) or at the date of radical surgery whichever occur last. Participants who did not have any baseline tumor assessments (imaging or biopsy) and did not undergo radical cystectomy for other reason than worsening/progression of disease will be censored on their date of randomization. Participants who did not have any on study tumor assessments (imaging or biopsy) and did not die will be censored on their date of radical cystectomy (or randomization date if no radical cystectomy performed).

Time frame: From randomization up to first EFS event (up to approximately 30 months)

Overall Survival (OS)

Overall Survival (OS) is defined as the time between the date of randomization and the date of death. For those without documentation of death, OS will be censored on the last date the participant was known to be alive. OS was not calculated for Arm A and Arm B because the number of events did not meet the threshold due to early study termination. In lieu of OS, time to death is reported as a Post-Hoc endpoint.

Time frame: From randomization to study completion, up to approximately 40 months

The Number of Participants Experiencing Adverse Events (AEs)

An Adverse Event (AE) is defined as any new untoward medical occurrence or worsening of a pre-existing medical condition in a clinical investigation participant administered study treatment and that does not necessarily have a causal relationship with this treatment. Adverse events are graded on a scale from 1 to 5, with Grade 1 being mild and asymptomatic; Grade 2 is moderate requiring minimal, local or noninvasive intervention; Grade 3 is severe or medically significant but not immediately life-threatening; Grade 4 events are usually severe enough to require hospitalization; Grade 5 events are fatal.

Time frame: from first dose to 100 days following last dose (up to approximately 20 months)

The Number of Participants Experiencing Serious Adverse Events (SAEs)

A Serious Adverse Event (SAE) is defined as any untoward medical occurrence that, at any dose results in death, is life-threatening (defined as an event in which the participant was at risk of death at the time of the event; it does not refer to an event which hypothetically might have caused death if it were more severe), requires inpatient hospitalization or causes prolongation of existing hospitalization.

Time frame: from first dose to 100 days following last dose (up to approximately 20 months)

The Number of Participants Experiencing Adverse Events (AEs) Leading to Discontinuation

An Adverse Event (AE) is defined as any new untoward medical occurrence or worsening of a pre-existing medical condition in a clinical investigation participant administered study treatment and that does not necessarily have a causal relationship with this treatment. Adverse events are graded on a scale from 1 to 5, with Grade 1 being mild and asymptomatic; Grade 2 is moderate requiring minimal, local or noninvasive intervention; Grade 3 is severe or medically significant but not immediately life-threatening; Grade 4 events are usually severe enough to require hospitalization; Grade 5 events are fatal.

Time frame: from first dose to 100 days following last dose (up to approximately 20 months)

The Number of Participants Experiencing Immune-Mediated Adverse Events (IMAEs)

IMAEs are specific AEs that include pneumonitis, diarrhea/colitis, hepatitis, nephritis/renal dysfunction, rash, endocrine (adrenal insufficiency, hypothyroidism/thyroiditis, hyperthyroidism, diabetes mellitus, and hypophysitis), and other specific events, considered as potential immune-mediated events by investigator that meet the definition summarized below: * those occurring within 100 days of the last dose, * regardless of causality, * treated with immune-modulating medication (of note, endocrine AEs such as adrenal insufficiency, hypothyroidism/thyroiditis, hyperthyroidism, diabetes mellitus, and hypophysitis are considered IMAEs regardless of immune-modulating medication use, since endocrine drug reactions are often managed without immune-modulating medication). * with no clear alternate etiology based on investigator assessment, or with an immune-mediated component.

Time frame: from first dose to 100 days following last dose (up to approximately 20 months)

Worst Grade Clinical Laboratory Values

Clinical laboratory values by worst CTC grade are graded on a scale from 1 to 5, with Grade 1 being mild and asymptomatic; Grade 2 is moderate requiring minimal, local or noninvasive intervention; Grade 3 is severe or medically significant but not immediately life-threatening; Grade 4 events are usually severe enough to require hospitalization; Grade 5 events are fatal.

Time frame: From first dose to 100 days following last dose (up to approximately 20 months)