CCR6 is a C-C chemokine receptor primarily functioning as a ligand-binding receptor for CCL20, the only known high-affinity chemokine ligand 1. Upon CCL20 binding, CCR6 transduces signals through increased intracellular calcium and cAMP levels 23. Beyond chemokines, CCR6 also binds non-chemokine ligands including β-defensins (DEFB1, DEFB4, DEFB4A/B), which activate similar signaling pathways and regulate sperm motility 34. CCR6 is expressed on B cells, dendritic cells, innate lymphoid cells, regulatory T cells, and Th17 cells, mediating their chemotaxis to inflammatory sites 1. It plays critical roles in immune homeostasis and responses at mucosal surfaces, including recruitment of both pro-inflammatory Th17 and anti-inflammatory Treg cells to intestinal tissues and other inflammation sites 5. CCR6-CCL20 axis dysregulation is implicated in multiple autoimmune and malignant diseases. Genome-wide association studies demonstrate strong correlations between CCR6 expression and severity in inflammatory bowel disease, psoriasis, rheumatoid arthritis, and multiple sclerosis 1. In cancer contexts, CCR6+ cell infiltration supports tumor immunosuppression through Treg recruitment in hepatocellular carcinoma 6 and represents a dysfunctional T cell population in lung adenocarcinoma 7. Blocking CCR6-CCL20 interactions therapeutically reduces disease severity across autoimmune conditions 1.