PD-L1 gene alterations are associated with objective response following pembrolizumab treatment in relapsed/refractory DLBCL patients. (A) Incidence and mechanism of PD-L1 gene alterations among 29 DLBCL patients enrolled on the KEYNOTE-013 study of pembrolizumab. (B) Swimmer’s plot demonstrating response characteristics and PFS to pembrolizumab according to PD-L1 locus status. Arrow depicts ongoing response. (C) Positron emission tomography (PET) scan images before and after pembrolizumab treatment in a patient with a PD-L1 gene–amplified DLBCL prior to and following 4 cycles of pembrolizumab treatment. PD, progressive disease; PR, partial response; SD, stable disease.