Opdivo (nivolumab) plus Yervoy (ipilimumab) is dual immunotherapy targeting and blocking the immune checkpoints PD1 and CTLA‐4, and has been successfully applied in clinical cancer therapy,[1] including colorectal cancer,[2] hepatocellular carcinoma,[3] and non‐small cell carcinoma.[4] Less than 30% of cancer patients respond to immune checkpoint therapy, but treatment with Opdivo plus Yervoy at an optimum dosage ratio of 3:1 enhances antitumor efficacy. This evidence concerns the gene CTLA4 and cancer.