Adebrelimab ±Induction Chemotherapy Followed by Concurrent Chemoradiotherapy for Unresectable Locally Advanced ESCC

Inclusion Criteria: 1. Aged 18-70 years, male or female; 2. Have not received systemic or localized treatment in the past; 3. Histologically or cytologically confirmed esophageal squamous cell carcinoma (AJCC 8th edition clinical stage II-IVA). IVB stage thoracic esophageal cancer with supraclavicular lymph node metastasis only. No surgical resection or refusal of surgical resection; 4. ECOG score of 0-1; 5. Life expectancy ≥ 3 months; 6. Adequate organ function; 7. Fertile men and women must agree to use contraception during the study period and for six months after the last drug used in the study； 8. Subjects will voluntarily enroll in the study, sign an informed consent form, be compliant, and cooperate with follow-up visits. Exclusion Criteria: 1. Subjects with low body weight (BMI \<18.5kg/m2) or ≥10% weight loss in the 2 months prior to screening; 2. Esophageal lesions with significant invasion of neighboring organs (e.g., aorta, trachea), or deep and large ulcers with a high risk of bleeding or fistula formation, or previous esophageal perforation or fistula within 6 months prior to screening; 3. Prior treatment with immunotherapy; 4. Treatment with any other clinical investigational drug or participation in another interventional clinical study within 4 weeks prior to first use of study drug; 5. Planning to receive or have received a prophylactic or live attenuated vaccine within 4 weeks prior to the first dose of study drug; 6. Receiving corticosteroid hormone therapy within 2 weeks prior to first use of study drug; 7. Subjects who have received a previous tissue/organ transplant or allogeneic hematopoietic stem cell transplant; 8. Active, known or suspected autoimmune disease; 9. Uncontrolled cardiac clinical symptoms or disease; 10. Active or uncontrolled serious infection (≥ CTCAE grade 2 infection); 11. Subjects with active tuberculosis or a history of active tuberculosis infection within 12 months prior to screening, with or without treatment; 12. History of interstitial lung disease (except radiation pneumonitis not treated with hormonal therapy), or history of non-infectious pneumonia; 13. Active hepatitis B virus or hepatitis C virus infection. Positive HIV test or known acquired immunodeficiency syndrome (AIDS); 14. Prior history of other malignancies within 5 years (except non-melanoma skin cancer, limited prostate cancer, or any early stage tumor treated by radical resection); 15. Known hypersensitivity to any of the investigational drugs or excipients; 16. The presence of other serious physical or mental illnesses or abnormal laboratory tests that may increase the risk of participation in the study or interfere with the results of the study, and subjects who, in the opinion of the investigator, are unsuitable for participation in this study.