The results showed that the side effects of anti-CTLA-4 combined with anti-PD-1 was higher than that of monotherapy (p < 0.00001), including fatigue (p < 0.00001), nausea (p = 0.02), diarrhea (p < 0.0001), colitis (p < 0.0001), rash (p = 0.0004), elevated ALT (p < 0.00001), elevated AST (p < 0.00001), elevated lipase (p = 0.01) significantly increased, but no significant difference between the side effects of anti-CTLA-4 combined with anti-PD-L1 and monotherapy (p = 0.34). This evidence concerns the gene CTLA4 and colitis.