CD274 and head and neck squamous cell carcinoma: However, both of these biomarkers have limitations in clinical practice, as p16 assay does not justify therapy stratification, and PD-L1-targeting immunotherapies are applicable to only a small proportion of HNSCC patients with advanced stage of the cancer (Chow, 2020; Bozec et al, 2019; Gillison et al, 2019; Mylly et al, 2022; Burtness et al, 2019).