CTLA4 and neoplasm: Treg cells prevented the maturation of antigen-presenting cell by expressing CTLA-4, or produced inhibitory cytokines and adenosine anti-tumor immunity to participate in tumor development and development.109 Treg-derived exosomes had also been implicated in immunosuppressive functions.110,111 Treg cell exosomes miRNA (Let-7d) strongly inhibited Th1 cell activity by inhibiting COX-2-mediated IFN-γ production.112 Macrophages are the major immune cells that regulate inflammation in the TME, including two broad phenotypes, M1 and M2.