The top 20 AUC values between both genders across four age groups in three types of immune cells displayed that the mitochondrial activities in mono changed more strikingly than those in CD4.T and CD8.T (mono > CD4.T ≈ CD8.T) in severe or critical COVID‐19 patients (prog and conv) (Figure 3A, Supporting Information Figure S5, Tables [Link], [Link]), which was similar to the sex‐biased change in immune activities during disease prog (Figure 1E). This evidence concerns the gene CD8A and COVID-19.