CD274 and head and neck squamous cell carcinoma: He et al. [54] found that high PD-L1 expression in OSCC was not related to OS, Tang et al. [53] demonstrated that the higher PD-L1 expression in tumor cells indicated a better DFS of OPSCC, and Yang et al. [71] claimed that the positive PD-L1 expression might predict better PFS in patients with advanced HNSCC.