CXCR6 and neoplasm: The chemokine receptors CCR6, CCR7, CXCR3, CXCR4, CXCR5, and CXCR6 have the highest expression across lymphocytes (Supplementary Fig. 14a), and CCR8, a known hallmark of tumour infiltrating Treg cells, is exclusively expressed on Treg cells35.