CD274 and post-transplant lymphoproliferative disease: Intriguingly, recent research has implied a significant role of non‐malignant tumor‐associated PD‐L1‐positive macrophages in, that is, Hodgkin's disease, with respect to prognosis, suggesting that with a higher amount of PD‐L1‐positive macrophages response to chemotherapy becomes poorer.36 Of the 4 p‐PTLD cases 3 showed, at least, persisting disease.