CD8A and infection: In the skin, following infection with vaccinia virus (VV) or herpes simplex virus, TRM develop from CD8+ T cell effectors (TEFF) that expand following priming in the lymph node and are recruited into the skin by inflammatory signals where they preferentially reside in the epidermis (Jiang et al., 2012; Allan et al., 2003; Bedoui et al., 2009; Liu et al., 2006; Reynoso et al., 2019; Gebhardt et al., 2011; Hirai et al., 2020).