This study is looking at how well a new drug, BMS-986365, works compared to other treatments chosen by doctors for men with a type of prostate cancer that has spread and is resistant to standard hormone therapy. The main goal is to see how long the cancer takes to grow by using pictures from scans, known as radiographic progression-free survival (rPFS). In the first part of the study, participants will be split into three groups to receive either one of two doses of BMS-986365 or a treatment chosen by their doctor. In the second part, participants will be divided into two groups to receive either the selected BMS-986365 dose or the treatment chosen by their doctor.

• The study has two main parts and participants will be randomly assigned to different treatment groups.
• Participants need to have prostate cancer that has spread and meets specific medical criteria.
• Participants should not have major heart issues, brain, or liver metastases.