CD274 and neoplasm: The tumor rejection was correlated both to changes in the tumor cells, like an upregulation of MHC class I surface expression (85) and modulation of PD-L1 expression (86) that render tumor cells more sensitive to cytotoxic T lymphocytes (CTLs) as well as to alterations in the TME, which reverted the immune suppressive conditions and allowed recruitment of effector cells (87, 88).