CD274 and neoplasm: Ligon et al., utilizing functional cytometry and immunohistochemistry, identified an immunosuppressive niche at the periphery of OS pulmonary metastases, enriched with M2 macrophages (M2); polymorphonuclear MDSC; and LAG-3-, TIM-3-, and PD-L1-expressing tumor-infiltrating lymphocytes (TILs), which correlated with worse progression-free survival [13].