CD274 and neoplasm: In classical Hodgkin lymphoma, EBV-positive tumors are associated with a high density of PD-L1–positive macrophages and display a characteristic T-helper 1 (Th1) anti-tumor immune signature, marked by increased CD8 + T-cell infiltration and coordinated expression of the canonical Th1 transcription factor T-bet (TBX21), interferon-gamma (IFNG), and the IFN-γ-induced immunosuppressive enzyme indoleamine 2,3-dioxygenase [16, 17].