In mild vs critical COVID-19, we observed that amongst several other pathways, IFN- (type I and II), interleukin (e.g., IL12 and IL6) and oligoadenylate synthetase (OAS) antiviral response signaling was increased in CD8+ TRM- and TEX-lineages (Fig. 5k; Supplementary information, Fig. S4b, e). Here, CD8A is linked to COVID-19.