Inclusion Criteria:  •≥18 years；  Esophageal squamous cell carcinomas； After radical treatment including surgery or definitive chemoradiotherapy Definition of oligometastases：≤3 metastases, including tumor beds and recurrent anastomotic sites；regional lymph node is defined as one metastatic site（AJCC8th, supraclavicular, mediastinal, abdominal）；metastases lesion in liver, lung, bone and brain is no more than 1. Karnofsky performance status(KPS)≥ 70； No immunotherapy were performed after recurrence； a white-cell count of at least 3500G/L, a hemoglobin concentration of at least 100 g/L, a platelet count of at least 100,000/lL, aspartate aminotransferase and alanine aminotransferase levels of within 1.5 times the upper limit of normal, a serum bilirubin level of 1.5 mg/dL or less, a creatinine level of 1.1 mg/dL or less; Hepatitis virus indicators: normal or hepatitis virus DNA titer less than 500 at the same time in an infectious disease hospital, and with the consent of the doctor can be treated；  Exclusion Criteria:  Pregnancy, possible pregnancy, or breast-feeding; Psychological, family, social and other factors lead to uninformed consent; An esophageal mediastinal fistula and/or an esophageal tracheal fistula prior to treatment; Serious complications such as ischemic heart disease, arrhythmias, or other types of heart disease requiring treatment; liver cirrhosis; interstitial pneumonia or pulmonary fibrosis; active gastrointestinal bleeding; mental disorders being treated with antipsychoticagents or requiring treatment; Controlled diabetes mellitus; A history of autoimmune disease, autoimmune disease (such as colitis, hepatitis, hyperthyroidism, including but not limited to these disease or syndrome) and a history of immune deficiency, including test positive for HIV, or has other acquired, congenital immunodeficiency disease, or have a history of organ transplantation and the history of allogeneic bone marrow transplantation; A history of interstitial lung disease and a history of non-infectious pneumonia; Active hepatitis B (HBV DNA ≥ 2000 IU/mL or 104 Copies /mL), hepatitis C ;(positive HCV antibody and HCV-RNA above the detection threshold of the assay） Any situation that is unstable or may compromise patient safety and compliance ; Active infections, such as active tuberculosis, are present;