CCL2 and neoplasm: This review systematically summarizes common regulatory mechanisms and tumor-specific variations in TAMs across these three malignancies, emphasizing the dual-origin developmental trajectories of tissue-resident macrophages and monocyte-derived macrophages, the CCL2-CCR2 and CSF1-CSF1R core signaling axes, and the regulation of TAMs' functional polarization by hypoxia and metabolic reprogramming.