CTLA4 and colitis: Within the context of immunotherapy, early work demonstrated the potential impact of certain gut microbial taxa such as Bacteroides to mitigate irAE, such as colitis, within preclinical models in response to anti-CTLA4 therapy; when mice treated with broad spectrum antibiotics underwent reconstitution with Bacteroides species associated with an improved response, there was a reduction in the histopathological signs of immune colitis, pointing to an efficacy–toxicity uncoupling effect mediated by Bacteroides [95].