CD274 and neoplasm: The expression of PD-L1 on tumor cells diminished tumor rejection by CD8 T cells but did not influence NK cell-mediated rejection, as they were capable of eliminating PD-L1 WT and KO tumor cells with similar efficiency, arguing against the claim that the co-inhibitory receptor PD-1 would play an inhibitory role in NK cell-mediated antitumor responses.