* Under 18 years of age; ECOG is greater than 2;
* The diagnosis of esophageal cancer is not supported by pathological biopsy or image examination;
* Salvage surgery was performed after tumor recurrence;
* The patient has any active autoimmune disease (such as the following, but not limited to: autoimmune hepatitis, interstitial pneumonia, uveitis, enteritis, hepatitis, hypophysitis, vasculitis, nephritis, hyperthyroidism; The patient had vitiligo; Those with complete remission of asthma in childhood can be included without any intervention in adulthood; Patients with asthma requiring medical intervention with bronchodilators are not included);
* Patients who were taking immunosuppressants or systemic hormone therapy for immunosuppressive purposes (doses \>10mg/ day of prednisone or other therapeutic hormones) and continued to use within 2 weeks before enrollment;
* Patients with severe and/or uncontrolled concomitant disease of grade 3 or higher, including: poor blood pressure control, myocardial ischemia or myocardial infarction, arrhythmia, active or uncontrolled severe infection; Liver diseases such as decompensated liver disease, active hepatitis B (HBV-DNA≥104 copy numbers /ml or 2000IU/ml), or hepatitis C (hepatitis C antibody positive and HCV-RNA above the lower detection limit of analytical methods);
* Pregnant or lactating women;
* Patients who have a history of psychotropic drug abuse and cannot quit or have mental disorders;
* Patients who have participated in clinical trials of other drugs within four weeks; .Patients or family members refused to participate in the study.