The purpose of this study is to test the the efficacy and safety of sintilimab in combination with chemoradiation before surgery for esophageal cancer.

Inclusion Criteria:

• Histologically or cytologically confirmed esophageal squamous carcinoma
• 18≤age≤75
• ECOG PS is 0-1
• TanyN+M0 or T3-4NanyM0 tumors
• Patients must have surgically resectable disease treatable by esophagectomy, as assessed by a thoracic surgeon
• No prior chemotherapy,radiotherapy and immunotherapy
• Disease must be clinically limited to the esophagus
• No esophageal perforation and no active esophageal bleeding
• No interstitial pneumonia or history of interstitial pneumonia
• FEV1>1.2L
• Adequate organ function defined at baseline as: WBC ≥3,000/ L，ANC ≥1,500/ L，Platelets ≥100,000/ L，Hb ≥9 g/dl； Calculated creatinine clearance >40 ml/min using Cockcroft-Gault method: Males: Creatinine CL = Weight (kg) x (140 - Age) . (mL/min) 72 x serum creatinine (mg/dL)Female：Creatinine CL (mL/min) = Weight (kg) x (140 - Age) x 0.85 72 x serum creatinine (mg/dL)；Total serum bilirubin ≤1.5 mg/dL， AST/ALT ≤2.5× upper limit of normal，Mean QT interval corrected for heart rate (QTc) <470 ms calculated from 3 ECGs using Frediricia's Correction
• Able to provide written informed consent
• Subject is willing and able to comply with the protocol for the duration of the study including undergoing treatment and scheduled visits and examinations including follow up

Exclusion Criteria:

• Previous treatment with chemotherapy, radiotherapy or immunotherapy
• Cervical esophageal cancer
• Esophageal perforation or active esophageal bleeding
• Interstitial pneumonia or history of interstitial pneumonia
• Patients with evidence of metastatic disease
• Chronic Hepatitis B or C infection (e.g. Hepatitis B surface Ag positive or detectable viral load for Hepatitis B or C). Patients with prior evidence of Hepatitis B or C without active infection are eligible
• Autoimmune diseases (such as systemic lupus erythematosus, rheumatoid rthritis, inflammatory bowel disease, autoimmune thyroid disease), but allow the following diseases to enter the next stage of screening: type I diabetes, skin diseases without systemic treatment (such as vitiligo, psoriasis)
• 14 days before the first dose, the patient had an active infection that required systemic treatment
• Inability to understand or may not comply with test requirements