PDCD1LG2 and Hodgkins lymphoma: The PD-1 pathway is crucial in the pathogenesis of HL because chromosome 9p24.1 alterations in RS cells result in the overexpression of PD-L1 and PD-L2 [17, 18], and PD-1 is expressed on immune cells in the HL tumor microenvironment [19, 20].