CD8A and COVID-19: When analysing disease-specific transcriptional signatures in CD8+ T cells, the authors found that biological pathways for responses to interferon (IFN)-I and -II were more associated with the influenza-specific cellular cluster, whereas pathways for the response to tumour necrosis factor (TNF) or interleukin-1β (IL-1β) were more prominent in COVID-19-specific clusters (24).