These observations have thus far shown some level of translatability to antitumor effects in PD-1/L1-experienced patients (e.g., metastatic melanoma) and a promising signal in combination with pembrolizumab in select patients with PD-1/L1–naïve HNSCC, with an overall response rate of 24%, and a disease control rate ≥18 weeks of 47% (43). This evidence concerns the gene PDCD1 and head and neck squamous cell carcinoma.