This may be one reason that PD-1 inhibition in DLBCL has been effective when directed at specific subtypes, including primary mediastinal large B-cell lymphoma, T-cell/histiocyte-rich large B-cell lymphoma, and EBV-positive lymphoma (15, 16, 36, 38–41). Here, PDCD1 is linked to diffuse large B-cell lymphoma.