CD274 and post-transplant lymphoproliferative disease: A colon biopsy taken 54 months later (Figure 3D‐F) demonstrated persistence of the PTLD category, but an increase of the number of PD‐L1‐positive macrophages from initially 20% to 30% (Figure 3B,E) and, in addition, a novel PD‐L1 positivity of the B‐cell blasts (Figure 3F); PD1 expression decreased (20% to 15%, Figure 3A,D).