RORA was identified as a key gut microbiota-related target, which was consistently downregulated in sepsis with the highest diagnostic AUC across datasets, mainly expressed in effector T cells and NK cells, and positively correlated with CD8 + T cell/NK cell infiltration (<i>R</i> = 0.419 and 0.352, respectively). The gene discussed is CD8A; the disease is Sepsis.