PDCD1 and neoplasm: These tumor-infiltrating NK cells (TINK) (identified based on hCD45+ expression (Fig. EV3A,B)) obtained from excised tumors on day 18 exhibited significantly reduced CD107a levels (Figs. 3C and EV3B,C), coupled with drastically upregulated PD-1 expression relative to the naive NK, indicating an “exhausted” phenotype (Fig. 3D).