Indeed, programmed cell death protein 1 (PD-1), Lymphocyte-Activation Gene 3 (LAG-3), and TIGIT expression is higher in COVID-19 patients compared to healthy controls, while DNAM-1 and NKG2D-expressing NK cells are decreased in frequency (Figure 1) (54, 66, 70). Here, LAG3 is linked to COVID-19.