CD274 and head and neck squamous cell carcinoma: Recently, a significantly increased survival of PD‐L2‐positive head and neck squamous cell carcinoma (HNSCC) patients treated with the PD1‐inhibitor pembrolizumab was shown.8 In hepatocellular carcinoma and in gastric adenocarcinoma, both increased PD‐L1 and PD‐L2 expression were associated with inferior prognosis,10, 11 outlining the role of PD‐L2 as immunosuppressive and cancer‐promoting signaling molecule.