Inclusion Criteria:
* Histologically confirmed localized ESCC that is suitable for cCRT, including: stage II-IVA (AJCC version 8) inoperable ESCC (medically unfit for surgery or refusing surgical intervention);;
* Aged 18-70, both sexes;
* ECOG score 0-1
* The presence of measurable and/or nonmeasurable lesions that met the definition of RECIST1.1;
* Adequate organ and bone marrow function, meeting the following definitions:
1. Blood routine (no blood transfusion, no granulocyte colony-stimulating factor \[G-CSF\], and no other drugs were used within 14 days before treatment);Absolute neutrophil count (ANC) ≥1.5×109/L;Hemoglobin (HB) ≥9.0 g/dL;Platelet count (PLT) ≥100×109/L;
2. Blood biochemistry Creatinine clearance rate ≥60 mL/min;Total bilirubin (TBIL) ≤ 1.5×ULN;Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) level ≤2.5×ULN;
* Expected survival time \> 6 months;
* Fertile female subjects and male subjects with partners of reproductive age are required to use a medically approved contraceptive method during the study treatment period and for at least 3 months after the last treatment;
* Patients who volunteered to participate in this study and signed the informed consent form.
Exclusion Criteria:
* A history of fistula caused by primary tumor invasion;
* Presence of clinically uncontrolled pleural effusion, pericardial effusion, or ascites that required repeated drainage or medical intervention (within 2 weeks before randomization);
* Known intolerance or resistance to chemotherapy specified in the trial protocol;
* have received any other ESCC antitumor therapy (e.g., therapy targeting PD-1, PD-L1, PD-L2 or other tumor immunotherapy, radiotherapy, targeted therapy, ablation or other systemic or local antitumor therapy);
* Patients with active autoimmune disease or a history of autoimmune disease that may relapse, or a known history of allogeneic organ transplantation or allogeneic hematopoietic stem cell transplantation;
* History of interstitial lung disease, non-infectious pneumonia or uncontrolled systemic diseases, including pulmonary fibrosis and acute lung disease;
* Severe chronic or active infection (including tuberculosis infection) requiring systemic antimicrobial therapy, antifungal therapy or antiviral therapy before enrollment;
* Known history of HIV infection;
* Other malignancies (except cured basal cell carcinoma of the skin, carcinoma in situ of the breast and carcinoma in situ of the cervix) in the past 5 years;
* Received live vaccine within 28 days before enrollment;
* while participating in another therapeutic clinical trial.
