In particular, Agarwal J. et al. [24] showed the useful monitoring of T-cell populations and the CD8 subset to differentiate the COVID-19 patients’ severity, highlighting the increase in the CD8 subsets Tc Naïve-Tim3+, Tc EM-Tim-3+ and Tc CM-Tim-3+ in severe patients compared to mild patients [24]. The gene discussed is HAVCR2; the disease is COVID-19.