CTLA4 and colitis: Microbial dysbiosis has been reported as a potential pathophysiology of ICIs-associated colitis.200,201 Anti-CTLA-4 treatment in mice leads to a decrease in the abundance of Bacteroidales and Burkholderiales, while supplementation with Bacteroides fragilis and Burkholderia cepacia can alleviate pathological changes without affecting the antitumor effect.202