STAT3 and classic Hodgkin lymphoma: PD-L1 is regulated by various molecules, such as STAT3 in T-cell lymphoma and melanoma (29), STAT and AP-1 in classical Hodgkin lymphoma (30), the ZEB1 axis in non-small-cell lung cancer (31), PI3K in glioma (32), and Myc in multiple tumors (33).