CD274 and neoplasm: On the basis of these findings, we validated the PD-L1 expression in PMBC-T cells (Supplementary Fig. 5) and performed an in vitro T cell-killing assay by co-culturing these effector T cells with PD-L1-knockout BT549 (human TNBC cell line) cells to exclude the interference from tumor cell-derived PD-L1.