Both CTLA-4 and PD-1/PD-L1 blockade can induce long lasting tumor responses in the absence of vaccination, suggesting that endogenous tumor-specific T cells exist in a substantial proportion of patients and that these T cells, once uncoupled from the inhibitory effect mediated by CTLA-4 and/or PD-1/PD-L1 can mediate effective tumor cell lysis (2, 3, 12–15). This evidence concerns the gene CTLA4 and neoplasm.