CTLA4 and colitis: Combination therapy and anti-CTLA-4 monotherapy pose higher risks.197,198 Notably, FMT can reshape the gut microbiota and improve clinical symptoms, suggesting the therapeutic potential of microbial modulation.199 Mechanistically, some viewpoints suggest that not only toxic reactions to intestinal tissue but also changes in the gut microbiota caused by ICIs may affect the pathogenesis of colitis.