Checkpoint inhibitor-induced side effects such as diarrhea and colitis occur in up to 30% of patients. We present a case of recurrent episodes of checkpoint inhibitor-induced colitis and subsequent Fournier gangrene that resolved after ileostomy formation. Once the Fournier gangrene and colitis had resolved, the ileostomy was reversed. However, within only 4 days, another serious flare-up of colitis occurred, necessitating emergent re-formation of the ileostomy. Expertise in the management of side effects of immune checkpoint inhibitor therapy is currently limited. Although most side effects are mild to moderate and transient, a minority of patients suffer from life-threatening complications, such as colitis. The creation of an ileostomy might be a valid treatment option in severe or recurrent colitis due to immune checkpoint inhibitor therapy. Intestinal diversion surgery may be useful if conservative treatment has failed, similar to other forms of immune-mediated intestinal inflammation.