Severe COVID-19 patients exhibited elevated IFNγ, Granzyme B, and KIR2DL1 expression in NK cells compared to controls (P < 0.005), while LAMP1 was unchanged (P > 0.05). NK cells from deceased patients exhibited significantly lower expression levels of LAMP1 and Granzyme B (P < 0.05). Here, KIR2DL1 is linked to COVID-19.