CCL18 is a C-C motif chemokine that functions as a selective lymphocyte chemoattractant with critical roles in immune regulation and tumor biology. Primarily, CCL18 attracts naive T-lymphocytes and B-cells but not monocytes or granulocytes, facilitating their migration toward dendritic cells and activated macrophages in lymphoid tissues [UniProt]. Mechanistically, CCL18 is predominantly secreted by M2 alternatively-activated macrophages 12 as part of their anti-inflammatory cytokine profile alongside CCL17 and CCL22 3. In disease contexts, CCL18 expression correlates with immunosuppressive microenvironments across multiple malignancies. In pancreatic cancer metastasis, CCL18+ lipid-associated macrophages contribute to pro-tumor environments 4, while in gastric cancer, CCL18+ M2 macrophages interact with cancer stem cells to promote therapeutic resistance and inferior prognosis 5. Notably, CCL18+ macrophages represent terminal immunosuppressive populations that enhance tumor metastasis 6. In atopic dermatitis, elevated serum CCL18 levels correlate with disease severity, with CCL18-expressing M2 macrophages participating in leukocyte infiltration patterns 7. Clinically, lactate-stimulated macrophages upregulate CCL18 expression via H3K18 lactylation to promote ovarian cancer progression 8, suggesting CCL18 as a potential therapeutic target in cancer and inflammatory diseases.