Colitis is also among the most frequent and problematic immune-mediated adverse events that are associated with dual checkpoint inhibition and a combination of anti-CTLA4 and anti-PD-1 monoclonal antibodies has been shown to exacerbate dextran sulfate sodium-induced autoimmune colitis in mice (Perez-Ruiz et al., 2019; Postow et al., 2018). The gene discussed is CTLA4; the disease is colitis.