Whereas a recent study reported an increase in NKG2C expression and a corresponding decreased expression of the adaptive NK cell–related marker FcεR1ɣ (41), we here provide a deep dissection of the adaptive NK cell phenotype, highlighting that despite their lower responsiveness to cytokines (40), a significant percentage of adaptive NK cells (up to 45%) actively proliferate in COVID-19 patients, albeit at a lower rate compared with nonadaptive NK cells. The gene discussed is KLRC2; the disease is COVID-19.