While secondary and exploratory analyses are still ongoing for IMBassador250, similar phase I/II clinical trials that involve anti-PD-1/PD-L1 antibodies, including the trials that led up to IMBassador250, serve to highlight mechanisms of prostate cancer resistance to anti-PD-1/PD-L1 CPIs. The gene discussed is PDCD1; the disease is Familial prostate cancer.