Recent study reported mucosal-associated invariant T (MAIT) cells in particularly are highly activated in COVID-19 patients, and corelated with cytotoxicity by producing IFN-γ, Granzyme B, TNF-α cytokines, and with the severity and mortality of SARS-CoV-2 (Flament et al., 2021). Here, IFNG is linked to COVID-19.