S100A9 and bacterial infectious disease: The myeloid cells, acting as the primary defense against bacterial infection in the synovium, are believed to play a crucial role in the development of PJI.[60] After re‐clustering, our results revealed the presence of seven distinct subpopulations in myeloid cells, including C1Q+myelo (C1QA, C1QB and C1QC), CCL+myelo (CCL3, CCL4 and TNF), MSTR (HSPS1, HSPD1 and HSPA1A), Mono (TMP1 and HCST), MDSCs (S100A8, S100A9 and FCN1), DCs (FCER1A, CD1C, HLA‐DQA1), OCs (MMP9, ACP5 and NFATC1) (Figure 2a,b; Figure S2b, Supporting Information).