Clinically, pembrolizumab has demonstrated efficacy in recurrent or metastatic head and neck squamous cell carcinoma (HNSCC), particularly in patients with high PD-L1 expression, as highlighted in the KEYNOTE-048 trial, where pembrolizumab alone or in combination with chemotherapy improved OS compared with cetuximab plus chemotherapy [119]. Here, CD274 is linked to head and neck squamous cell carcinoma.