CCL22 and hepatocellular carcinoma: Additionally, Treg cells expand during chronic HBV infection, stimulated by cytokines (e.g., TGFβ, IL-10, and C-C motif chemokine ligand 22 (CCL22)) secreted by other innate cells, to prevent excessive antiviral immune responses and establish an immunosuppressive microenvironment for HCC initiation and progression [42].