CCL8 (C-C motif chemokine ligand 8), also known as monocyte chemotactic protein-2 (MCP-2), is a chemotactic cytokine that recruits monocytes, lymphocytes, basophils, and eosinophils 1. It functions as a ligand for CC chemokine receptors, particularly CCR1, and exhibits dual roles in immune regulation 2. CCL8 mediates cell migration and chemotactic signaling through receptor binding and can modulate intracellular calcium homeostasis 1. Mechanistically, CCL8 expression is transcriptionally regulated under hypoxic conditions within tumors 3. In the tumor microenvironment, CCL8 participates in self-reinforcing autocrine loops between tumor-associated macrophages (TAMs) and cancer cells 4, while also recruiting immunosuppressive myeloid cells and T regulatory cells 2. Notably, processed MCP-2(6-76) inhibits the chemotactic activity of related chemokines including CCL2, CCL5, and CCL7. Clinically, CCL8 dysregulation contributes to cancer progression, metastasis, and immune evasion 5. Elevated CCL8 is also associated with infectious diseases (HIV, tuberculosis), inflammatory disorders (graft-versus-host disease, idiopathic pulmonary fibrosis), and allergic diseases including asthma 1. Additionally, CCL8 serves as a shared biomarker in ischemic stroke and obstructive sleep apnea, with potential diagnostic value 6. CCL8 represents a therapeutic target for immune-related pathologies.