While PD-L2 is already targeted when the receptor PD-1 is inhibited, novel immune checkpoint inhibitors against HVEM should be tested in the future also for HNSCC, as in melanoma it was found that HVEM has a broader expression than even PD-L1 and serves as a negative prognostic marker [56]. This evidence concerns the gene PDCD1LG2 and head and neck squamous cell carcinoma.