Our results revealed that the percentage of effector CD8+ T (Teff) (CD3+ CD8+ CD45RA+ CD62L-) cells was significantly lower, whereas that of naive CD8+ T cells was obviously greater in P210-elevated CML patients after contracting COVID-19 than in non-P210-elevated CML patients or health controls (Figures 4E–H). The gene discussed is SELL; the disease is COVID-19.