PDCD1 and cancer: Moreover, ipilimumab in combination with nivolumab (anti-PD-1 mAb) is approved in the US for the treatment of unresectable or metastatic melanoma, advanced RCC, and microsatellite instability high or mismatch repair deficient metastatic colorectal cancer (https://www.cancer.gov/about-cancer/treatment/drugs/ipilimumab).