Overall, our results suggest promising efficacy and a manageable safety profile of SHR-1210 in pretreated patients with metastatic ESCC. In addition, our exploratory gene analyses revealed that a tumor whose mutational burden falls in the range of most common tumor types could benefit from SHR-1210 therapy and that mutational load/neoantigen/neoepitope analysis could become potential predictive biomarkers for patients with this tumor type.