Pooled meta-analysis data suggest that diarrhea (13% vs. 33%) and colitis (1.4% vs. 9.1%) are less frequent with PD-1/PD-L1 inhibitors compared to CTLA-4 therapy, but symptoms persist longer (2 months vs. 1.4 months) [30,31,32]. This evidence concerns the gene CTLA4 and colitis.