CCL2 and neoplasm: In addition, the infiltration of TAMs is reported to be modulated by the CCL2-CCR2 axis to affect PD-1 signaling pathway, leading to immune evasion (91), and CCL18 released by TAMs can promote tumor proliferation through activating the JAK2/STAT3 pathway (86), all of which contribute to the unsatisfactory prognosis of patients with ESCC.