The incidence of irAE colitis is reported to be 0.7–1.6% with anti-PD-1 therapy, 5.7–9.1% with anti-CTLA-4 therapy, and nearly 13.6% with the combination of anti-PD-1/PD-L1 and anti-CTLA-4 therapies [8,9,10]. This evidence concerns the gene CTLA4 and colitis.