Sipuleucel-T (Sip-T) in Combination With N-803 in Metastatic Androgen Pathway Modulation Resistant (mAPMR) Prostate Cancer

Inclusion Criteria: * Histologically or cytologically confirmed prostate adenocarcinoma. * Imaging- or biopsy-proven metastatic disease. May have any type or location of metastases (bone, lymph node, visceral). * Prior treatment must include either orchiectomy or luteinizing hormone-releasing agonist or antagonist treatment with documented testosterone ≤ 50 ng/dL. * Eligible for standard of care Sipuleucel-T. * Recovery to baseline or ≤ grade 1 from toxicities related to any prior treatments, unless AEs are clinically nonsignificant and/or stable on supportive therapy. * At least 18 years of age. * ECOG performance status ≤ 2 * Adequate bone marrow and organ function as defined below: * Absolute neutrophil count ≥ 1,500 K/cumm without granulocyte colony-stimulating factor support * Platelets ≥ 100,000 K/cumm without transfusion * Hemoglobin ≥ 10.0 g/dL * Total bilirubin ≤ 1.5 x IULN * AST(SGOT) and ALT(SGPT) ≤ 2.5 x IULN * Calculated creatinine clearance ≥ 50 mL/min by Cockcroft-Gault * PSA ≤ 200 ng/mL. * Ability to understand and willingness to sign an IRB approved written informed consent document. Legally authorized representatives may sign and give informed consent on behalf of study participants Exclusion Criteria: * Rapidly progressing disease or symptomatic prostate cancer as assessed by the investigator. * Prior immunotherapy (e.g., anti-PD-1, anti-PD-L1, anti-CTLA4) within the 6 months prior to enrollment. * Prior systemic radiotherapy (such as Ra-223…