CD274 and head and neck squamous cell carcinoma: However, it remains unclear as to whether human papillomavirus (HPV) status is associated with improved clinical outcome of anti-PD-1 or anti-PD-L1 immunotherapy in HNSCC.<h4>Methods</h4>PubMed, EMBASE, Cochrane Library, and Web of Science were systematically searched up to February 28, 2021.