CD8A and viral infectious disease: Recent studies reported KLRG1hiCD127lo effector‐like long‐lived memory CD8+ T cells in mice with chronic viral infection that can survive long‐term, have robust effector function, and are effective in clearance of pathogens against rechallenge infection, and also sensitive to checkpoint blockade therapy (Olson et al, 2013; Hudson et al, 2019; Renkema et al, 2020).