A Study of Nivolumab Plus Ipilimumab, Ipilimumab Alone, or Cabazitaxel in Men With Metastatic Castration-Resistant Prostate Cancer (CheckMate 650)

Inclusion Criteria:

* Eastern Cooperative Oncology Group (ECOG) performance status 0-1
* Current evidence of metastatic disease documented by either bone lesions on radionuclide bone scan and/or soft tissue lesions on computerized tomography/magnetic resonance imaging (CT/MRI).
* Ongoing androgen deprivation therapy (ADT) with a Gonadotropin-releasing hormone (GnRH) analogue or a surgical/medical castration with testosterone level of ≤1.73nmol/L (50ng/dL)

For crossover phase for participants originally randomized to Arm D3 or Arm D4 only:

* Previously randomized to Arm D3 or D4; had histologic confirmation of adenocarcinoma of the prostate and evidence of Stage IV disease (as defined by American Joint Committee of Cancer criteria (AJCC criteria) prior to randomization

Exclusion Criteria:

* Presence of visceral metastases in the liver
* Active brain metastases or leptomeningeal metastases
* Active, known, or suspected autoimmune disease or infection
* Prior treatment with an anti-PD-1, anti-PD-L1, anti-PD-L2, or anti-CTLA-4 antibody, or any other antibody or drug specifically targeting T-cell co-stimulation or checkpoint pathways

For crossover phase for participants originally randomized to Arm D3 or Arm D4 only:

* Prior radiation therapy within 14 days prior to first dose of nivolumab combined with ipilimumab
* Have received systemic anti-cancer therapy after the last dose of study treatment (ipilimumab or cabazitaxel)

Other protocol-defined inclusion/exclusion criteria apply