ICIs, including agents such as ipilimumab (anti–CTLA-4), nivolumab and pembrolizumab (anti–PD-1), and atezolizumab (anti–PD-L), have revolutionised the management of patients with cancer, by targeting immune checkpoint inhibitory pathways including CTLA-4, PD-L and PD-L1 [5,8,9]. Here, CTLA4 is linked to cancer.