In this context, the CD56dimNKG2A−KIR+LIR-1+CD57+ NK cell subset, when derived from individuals previously exposed to pathogens, particularly HCMV, may include “memory-like” NK cells (that display certain functional characteristics reminiscent of adaptive immunity cells) (7) or PD-1+ NK cells (characterized by high surface expression of the PD-1 inhibitory checkpoint, and by impaired anti-tumor activity) (46). This evidence concerns the gene LILRB1 and neoplasm.