CD8A and viral infectious disease: After influenza virus infection, CD8+ TRM require continuous recruitment from the circulating memory pool to establish tissue resident cells, and this viral infection shows that Blimp-1, rather than Hobit, mediates the formation of TRM cells within the lungs [86], potentially through control of the lineage choice between TCM and TRM cells during the differentiation of influenza-specific CD8+ T cells [87].