CD8A and COVID-19: Our observations also described an abnormal CD8+ T cell profile in COVID-19 convalescents, which resulted in lower frequencies of effector CD8+ T cell subsets (TEMRA and Tc1), a higher senescent state (upregulated CD57 expression on ‘naïve’ and memory cell), and higher frequencies of CD8+ T cell subsets expressing lung tissue and mucosal tissue homing molecules (Tc2, Tc17, and Tc17.1).