CTLA4 and cancer: Clinical studies have shown that dual blockade of PD-1 and CTLA-4/LAG3/TIGIT/HAVCR2 enhanced the proliferation and function of CD8+T cells and tumor-infiltrating lymphocytes as compared with single blockade and could provide survival benefit as compared with PD-L1 blockade alone for patients with PD-L1-positive cancers (Chauvin et al., 2015; Andrews et al., 2017; Chauvin and Zarour, 2020; Rodriguez-Abreu et al., 2020; Trüb et al., 2020).