Prostaglandin E2 (PGE2) and adenosine are released in large quantities by cancer cells and macrophages in hypoxic conditions, and inhibit T lymphocytes proliferation by activating G protein-coupled receptors and protein kinase A. Moreover, tumor infiltrate is enriched in Tregs, myeloid-derived suppressor cells (MDSC), TAM and TAN (tumor-associated macrophages and tumor-associated neutrophils) favoring tumor survival by the secretion of TGF-β, IL-10, nitric acid, and indoleamine dioxygenase 2–3. Here, IL10 is linked to neoplasm.