CTLA4 and neoplasm: Our group and others previously demonstrated that maximal anti-tumor activity of αCTLA-4 antibodies depends both on blockade of the CTLA-4 co-inhibitory molecule and on intra-tumoral depletion of Treg cells (Arce Vargas et al., 2018, Peggs et al., 2009, Selby et al., 2013, Simpson et al., 2013).