The best characterized adaptive NK cell subset in humans, expressing high levels of the activating receptor NKG2C, the activating counterpart of NKG2A that also binds to HLA-E (with lower affinity than NKG2A) (Guma et al., 2006; Beziat et al., 2013; Peppa et al., 2018) is driven by CMV infection. This evidence concerns the gene KLRC1 and cytomegalovirus infection.