The TME comprises a stromal compartment, which helps to establish the appropriate network required to support tumor development, including immunosuppressive cells, such as regulatory T cells, myeloid-derived suppressor cells, tumor-associated macrophages, neutrophils, and stromal fibroblasts, which secrete immunosuppressive factors and up-regulate inhibitory ligands, including PD-L1, which can suppress the effectiveness of ACT (34–36). The gene discussed is CD274; the disease is neoplasm.