CCL2 and cancer: To further verify whether TRAIL-R expression in cancer cells results in CCL2 production by tumor cells and thereby facilitates the accumulation of M2 macrophages in the TME, we knocked out TRAIL-R expression on the surface of tumor cells using CRISPER-Cas9 (Fig. S4B), and found that both 4T1-TRAIL-R-KO and CT26-TRAIL-R-KO cell lines blocked TRAIL-TRAIL-R axis-induced Ccl2 expression (Fig. 4J).