CD4 and infection: Detailed, IL‐10 has been reported to facilitate the formation of bacterial biofilm, thereby enabling S. aureus to escape from the host immune clearance.[101, 102, 103] IL35 could suppress the differentiation of CD4+T cells into Th17 cells, thereby dampening the immune response against infections.[104] TGF‐β suppressed the immune activities of Th1 and Th2 cell.[105] Our scRNA‐seq studies revealed a significant enrichment of genes involved in above cytokines in Treg from S. aureus PJI, meaning that the anti‐bacterial activity of host would be suppressed by the Treg.