ICOS and neoplasm: For example, tumor‐infiltrating Treg cells overexpress some surface molecules such as LAG3, TIGIT, CTLA4 or ICOS in both primary tumor or in metastatics when compared to circulating Treg cells.30 It should be noted that in human breast and colon cancer, infiltration by CCR8+ Treg and CCR4+ Treg cells is correlated with poorer prognosis, respectively.31, 32 Therefore, molecular targets to neutralise in Treg cells during tumor immunotherapy may differ given the type of tumors.