In particular, an excellent response to anti-PD-1 antibodies has been demonstrated for advanced cases with classical Hodgkin lymphoma (cHL), a defining feature of which is frequent copy number gains or amplifications involving PD-L1 and/or PD-L2, suggesting a close link between PD-L1/PD-L2 genetic alterations and the therapeutic response to these agents [6–8]. The gene discussed is PDCD1LG2; the disease is classic Hodgkin lymphoma.