Salvage Immunotherapy and Chemotherapy in Esophageal Squamous Cell Carcinoma Patients Nonresponding to Initial Neoadjuvant Chemoradiotherapy

Inclusion Criteria: 1. Diagnosed with Stage II/III carcinoma of the esophagus squamous cell carcinoma. 2. Completed pre-operative chemoradiotherapy followed by surgery 3. Diagnosed with residual pathologic disease after being surgically rendered free of 4. Disease with negative margins following complete resection 5. Nonresponding to initial neoadjuvant Chemoradiotherapy(TRG3 and TRG4) Exclusion Criteria: 1. Known or suspected history of active autoimmune diseases, autoimmune diseases (such as interstitial pneumonia, colitis, hepatitis, pituitaritis, vasculitis, nephritis, hyperthyroidism, hypothyroidism, including but not limited to these diseases or syndromes) 2. Have a history of immunodeficiency, including HIV positive, or other acquired, congenital immunodeficiency disease, or history of organ transplantation and bone marrow transplantation； 3. Interstitial lung disease, drug-induced pneumonia, radiation pneumonitis requiring steroid therapy or active pneumonia with clinical symptoms or severe pulmonary dysfunction； 4. There are clinical symptoms or diseases of the heart that are not well controlled, such as: (1) heart failure of NYHA class 2 or higher (2) unstable angina (3) myocardial infarction within 24 weeks (4) clinical need for treatment or Interventional supraventricular or ventricular arrhythmia； 5. Have a tendency to hereditary bleeding or coagulopathy. Clinically significant bleeding symptoms or clear bleeding tendency within 3 months prior to enrollment, such as gastrointestinal bleeding, hemorrhagic gastric ulcer, baseline fecal occult blood++ and above； 6. Has not fully recovered from toxicity and/or complications from any intervention prior to initiation of treatment (i.e., ≤ grade 1 or level required at baseline, excluding fatigue or hair loss); 7. Allergic reactions to test drugs for this application； 8. Pregnant or lactating women； Those whom the investigator considered unsuitable for inclusion。