Bloody diarrhea, mucorrhea, vomiting, fever, fatigue, or weight loss are the hallmarks of colitis: it is estimated that 54% of patients treated with anti-CTLA4 mAbs and the combination of anti-CTLA4 and anti-PD-1 experienced diarrhea, more frequently than anti-PD-1 monotherapy patients (with an incidence of 19%) [19]. Here, CTLA4 is linked to colitis.