To gain greater knowledge regarding the effect of a tumor microenvironment, detected through IHC or the FDG-PET related radiomics, on tumor PD-L1 expression, we conducted this study to investigate the associations between tumor PD-L1 expression, several protein biomarkers involving the pathogenesis of hypoxia, angiogenesis, and proliferation, and 18F-FDG PET-based textural features in patients with HNCs. This evidence concerns the gene CD274 and neoplasm.