GSEA revealed the enrichment of gene sets associated with T cell effector differentiation and T cell activation in severe COVID-19, whereas genes related to CD8+ T cell memory differentiation were enriched in mild COVID-19, indicating that CD8+ T cell fate is strongly directed toward a highly activated effector phenotype in severe SARS-CoV-2 infection (Figure 1F and Table S4). This evidence concerns the gene CD8A and COVID-19.