IL6 and neoplasm: Thirdly, neovascularization fails to compensate for enhanced oxygen consumption, and concurrent hypoxia potently declines the functions of TILs as a result of that hypoxia increases the expression of multiple inhibitory mediators for anti-tumor immune response, such as PD-L1, indoleamine 2, 3-dioxygenase (IDO), interleukin-6 (IL-6), and interleukin-10 (IL-10) (11).