CTLA4 and neoplasm: What is well known is that PC tissue is marked by large T cell inflammatory infiltrates within TE and TME participating in host defence mechanisms against tumor cells40,41 and that PD-1/PD-L1 pathway has a crucial role in the regulating of T cell activation during inflammatory processes33, in contrast to CTLA-4, which inhibits T cell activityduring the T cell priming phase41,42.