PDCD1 and diffuse large B-cell lymphoma: In a recent phase-2 study designed to evaluate the efficacy and safety of pembrolizumab as a humanized PD-1 mAb, 26 patients with relapsed chronic lymphocyte leukemia (CLL) (n = 16) and Richter’s transformation (RT) (n = 9, all were proven DLBCL) as transformed CLL were enrolled [76] (Table 2).