CCL16 is a CC-motif chemokine with selective chemotactic activity for monocytes and lymphocytes, but not neutrophils 1. The protein is primarily synthesized by hepatocytes and circulates as a full-length protein in blood, with a C-terminal extension that modulates glycosaminoglycan binding and biological activity 1. Mechanistically, CCL16 signals through CCR1 and other CC chemokine receptors on immune cells, inducing calcium flux and promoting cell migration 2. In monocytes, CCL16 uniquely stimulates CCL2 secretion in a G-protein-dependent manner, which IL-10 markedly enhances, promoting coordinated immune cell infiltration 2. CCL16 has dual roles in disease: it enhances anti-tumor CD8+ and CD4+ T cell responses to HER-2 when used to mature dendritic cells 3, yet elevated expression associates with hepatocellular carcinoma pathogenesis and inflammatory disorders including periodontitis 4. Notably, tumor-derived CCL16 activates macrophage ICAM-1 receptors, triggering JAK2-STAT6 pathway activation and IL24 secretion, which normalizes tumor vasculature and enhances immunotherapy efficacy when combined with anti-PD-1 antibodies 5. In pneumonia, CCL16 mediates LPS-induced inflammatory injury through the TLR4/NF-κB pathway, representing a therapeutic target 6. These findings establish CCL16 as a multifunctional regulator of immune-vascular cross-talk with complex pro- and anti-inflammatory properties depending on tissue context.