CD4 and neoplasm: CCR8 expression was shared by Treg cells infiltrating breast, lung and colorectal cancers, as well as in melanoma and in angiosarcoma.70, 86 Functionally, sorted tumour‐infiltrating CD4+ CD25+ Treg cells were able to migrate more robustly than Tconv cells towards the CCR8 ligand CCL1.70 Consistent with its tumour‐specific pattern of expression, robust CCR8 expression by Treg cells was shown to require TCR engagement as well as soluble tumour‐derived factors using tumour explant co‐cultures.