CD4 and atrial fibrillation: To further verify the recruitment effect of CXCL16/CXCR6 axis on Treg, we conducted multiplex immunofluorescence staining to indicate the co‐location of CXCL16‐expressing myeloid cells (CD68+) and CXCR6‐expressing Treg (CD4+FOXP3+) in PJI group, not in AF and OA groups (Figure 4j).