CCR8 and neoplasm: Moreover, CCR8+ Treg cells possessed a more tumor-reactive and immune-suppressive phenotype compared to FOXP3+ Treg cells, with relatively higher expression of exhaustion and cytokine receptor markers along with strong enrichment of IL-2-STAT5 signaling, which has been reported to be involved in CD8+ T cell exhaustion26 (Figure 5D; Table S15).