Extracellular ADO can exert effect on tumor immune microenvironment through multiple pathways [1, 13]: 1) Limiting cytotoxic activity of effective immune cells: ADO significantly reduces CD8+ T cells homing and inhibits NK cells by interfering with the process of granule exocytosis and reducing the ability of NK cells to adhere to tumor cells [14, 15]. Here, CD8A is linked to neoplasm.