PDCD1 and cancer: These findings were in line with our data that the CTLA-4|CD80/CD86 immune checkpoint proteins are increased in ADPKD1 compared with control (Figures 6 and 7) and current clinical findings from the cancer literature that show increased efficacy of combination therapy with FDA-approved anti–PD-1 plus anti–CTLA-4 versus monotherapy alone (18, 20, 35, 42, 43).