CXCL9, CXCL10, and SIGLEC1 uniquely secreted by C17 myeloid‐derived macrophage and C3 metastatic macrophages (APOC1+APOE+ macrophages) can bind to CXCR3 or SPN on the surface of T cells, thereby regulating multiple T‐cell functions, including T‐cell activation, proliferation, differentiation, trafficking and migration (Figure 6e,f),[38, 39, 40, 41] but their roles in ESCC metastasis remained unclear. Here, APOC1 is linked to esophageal squamous cell carcinoma.