Neoadjuvant Chemoradiotherapy Combined With CTLA-4 Monoclonal Antibody Plus PD-1 Monoclonal Antibody for Locally Advanced Esophageal Cancer

Inclusion Criteria: 1. Histologically confirmed resectable thoracic esophageal squamous cell carcinoma (ESCC); pretreatment clinical stage of T1-4aN1-3M0 or T3-4aN0M0 per the 8th edition of UICC staging system. 2. Treatment-naive patients without prior anti-tumor therapy. 3. Expected survival duration \> 6 months. 4. Aged between 18 and 75 years, either male or female. 5. Adequate function of major vital organs meeting the following laboratory criteria: 1. White blood cell (WBC) ≥4.0×10⁹/L; absolute neutrophil count (ANC) ≥1.5×10⁹/L; 2. Platelet count ≥100×10⁹/L; 3. Hemoglobin ≥9 g/dL; 4. Serum albumin ≥2.8 g/dL; 5. Total bilirubin ≤1.5 × ULN; ALT, AST and/or ALP ≤2.5 × ULN; 6. Serum creatinine ≤1.5 × ULN, or creatinine clearance \>60 mL/min. 6. Eastern Cooperative Oncology Group (ECOG) PS score: 0-1. 7. Capable of understanding the study protocol and signing written informed consent. 8. Absence of severe complications including active massive gastrointestinal hemorrhage, perforation, jaundice, bowel obstruction, or non-malignant fever \>38℃. 9. Female and male patients of childbearing potential must use effective contraception throughout relevant study period. 10. Good treatment compliance and availability for scheduled follow-up of efficacy and adverse events per study protocol. Exclusion Criteria: 1. Patients who have received prior anti-tumor therapies including chemotherapy, radiotherapy, surgery, immunotherapy, etc. 2. Patients with known or suspected hypersensitivity to any components of CTLA-4 inhibitors, sintilimab or other monoclonal antibodies, as well as chemotherapeutic agents (nab-paclitaxel and cisplatin). 3. Patients with pre-existing hemorrhagic disorders. 4. Patients with unresectable disease due to other uncontrollable conditions. 5. Female patients who are pregnant or breastfeeding. 6. Patients lacking capacity to provide informed consent due to psychological, familial or social reasons. 7. Patients with peripheral neuropathy graded ≥ Grade 2 per CTCAE criteria. 8. Patients with a prior history of other malignancies besides esophageal cancer, except for non-melanoma skin cancer, cervical carcinoma in situ, or previously cured early-stage prostate cancer. 9. Patients with more than 10 years of diabetes mellitus and poorly controlled blood glucose. 10. Patients with severe impairment of cardiac, pulmonary, hepatic or renal function, hematological diseases or cachexia that preclude tolerance to chemotherapy, radiotherapy or surgery. 11. Patients with active or past history of autoimmune diseases (including but not limited to colitis, hepatitis, hyperthyroidism), or history of immunodeficiency diseases (HIV positive, other acquired or congenital immunodeficiency disorders), or previous history of solid organ or allogeneic hematopoietic stem cell transplantation. 12. Patients with prior history of interstitial lung disease or non-infectious pneumonia. 13. Subjects with active hepatitis B (HBV DNA ≥ 2000 IU/mL or 10⁴ copies/mL) or active hepatitis C (HCV antibody positive with HCV-RNA above the lower limit of quantification of the assay).