RecruitingPhase 1Biological interventionTrial of pTVG-HP+Nivo+Targeted Ablation of Resistant Lesions in Non-Castrate RecurrentOMPCThe goal of this clinical trial is to learn whether an experimental vaccine called pTVG-HP ("vaccine" or "DNA vaccine"), combined with a drug called nivolumab can increase the cancer-fighting ability of a person's immune cells. The main question it aims to answer is whether the combination of medicines can get rid of metastatic tumors in participants with non-castrate, recurrent, oligometastatic prostate cancer. Participants will undergo: * Treatment with pTVG-HP * Treatment with Nivolumab * Radiation Therapy