CCR8 and neoplasm: Enrichment of highly suppressive tumor-infiltrating Treg cells with elevations in many immunological checkpoints, and highly expressed unique characteristic markers on the cell surface, including interleukin-1 receptor 2 (IL1R2), programmed death (PD)-1 Ligand 1, PD-1 Ligand 2, and CCR8 chemokineAssociation of high expression of Treg cell signature genes (LAYN, MAGEH1, or CCR8) in whole-tumor samples with a poor prognosis