Immunotherapy for Head and Neck Squamous Cell Carcinoma: Present and Future Approaches and Challenges.

Despite significant progress and improving outcomes in the management of head and neck squamous cell carcinoma (HNSCC), there are few effective treatment options for patients with recurrent or metastatic head and neck squamous cell carcinoma. The advent of immune checkpoint inhibitors has changed the treatment algorithm of head and neck squamous cell carcinoma and are approved in the frontline setting for recurrent and metastatic (R/M) head and neck squamous cell carcinomas. Although promising for some patients, most patients with R/M HNSCC do not derive clinical benefit from currently approved checkpoint inhibitors. Many studies are underway to identify the patient population that would benefit the most from immunotherapy as well as postimmunotherapy treatment failures, including novel combinations of immunomodulatory therapies. In this review, we summarize the clinical development of all major clinical trials of immunotherapy in HNSCC.