CCL22 (Chemokine (C-C motif) ligand 22) is a cytokine that plays a key role in immune system regulation and inflammation. It belongs to the C-C chemokine family and primarily functions to attract T cells, particularly regulatory T cells (Tregs), to sites of immune activation and inflammation by binding to the CCR4 receptor. CCL22 is produced by various cells, including dendritic cells, macrophages, and epithelial cells, and is involved in maintaining immune tolerance, tissue repair, and the regulation of allergic reactions. Its dysregulation has been associated with autoimmune diseases, cancer, and chronic inflammatory conditions.