CD274 and neoplasm: Furthermore, there exist numerous other mechanisms that induce immunosuppression, such as increased population of dysfunctional T-cell subsets which lack effector functions [46,47], metabolic alterations in the TME that can lead to suppression of T-cell responses by depriving essential nutrients [48], the presence of tumor-derived VEGF-C linked to metastatic advancement [49], and heightened expressions of PD-L1 (Figure 1) [50].