Biomarker-Driven Therapy With Nivolumab and Ipilimumab in Treating Patients With Metastatic Hormone-Resistant Prostate Cancer Expressing AR-V7

This phase II trial studies how well nivolumab and ipilimumab work in treating patients with hormone-resistant prostate cancer that has spread to other places in the body and express androgen receptor-variant-7 (AR-V7). Tumor cells expressing AR-V7 has been shown to be resistant to hormone therapy and some chemotherapy in patients with prostate cancer. Biomarker-driven therapy, such as nivolumab and ipilimumab, may work by blocking key biomarkers or proteins that help tumor cells to escape the immune system surveillance and this may help the immune system to kill tumor cells that express AR-V7.