PD-1 and PD-L1 inhibitors have emerged as promising treatments for patients with head and neck squamous cell carcinoma (HNSCC). We reviewed 11 trials which reported data on 1,088 patients (mean age 59.9 years, range 18-90). Our meta-analysis describes the efficacy of PD-1 and PD-L1 inhibitors in HNSCC, and suggests a possible difference in certain RECIST criterion between PD-1 and PD-L1 inhibitors.