Perioperative Cadonilimab Combined With Neoadjuvant Chemotherapy in Resectable Esophageal Squamous Cell Carcinoma (ESCC)

Inclusion Criteria:

* Be able and willing to provide written informed consent and to comply with all requirements of study participation (including all study procedures).
* ≥18 years old and ≤ 75 years (regardless of sex).
* Pathologically confirmed esophageal squamous cell carcinoma, assessed as resectable.
* Adequate pulmonary function.
* Adequate tumor tissue samples.
* ECOG performance status of 0-1.
* Adequate organ function.
* Within 7 days prior to the first dose, women of childbearing potential must have a negative urine or serum pregnancy test and agree to use effective contraception during the study treatment period and for 120 days after the last dose.

Exclusion Criteria:

* Presence of suspected distant metastatic lesions, or locally advanced unresectable disease.
* Histologically confirmed as other pathological types.
* Previous surgery precludes the use of gastric substitution for esophageal reconstruction in the current procedure.
* History of other malignant tumors within the past 5 years.
* Within 4 weeks prior to randomization, presence of conditions such as severe esophagogastric varices, active ulcers, unhealed wounds, gastrointestinal perforation, or intestinal obstruction.
* Active or documented history of inflammatory bowel disease.
* Clinically symptomatic or recurrent pleural, pericardial, or ascitic fluid requiring drainage.
* Uncontrolled concurrent illnesses.
* Acute exacerbation of chronic obstructive pulmonary disease within 4 weeks prior to randomization.
* History of myocardial infarction, unstable angina, congestive heart failure within 12 months prior to day 1 of study treatment.
* History of severe bleeding tendency or coagulation dysfunction.
* Arterial thromboembolic events within 6 months prior to randomization.
* History or current presence of non-infectious pneumonitis/interstitial lung disease requiring systemic glucocorticoids.
* Known psychiatric disorders, drug abuse, or substance addiction.
* Pregnant or lactating women.
* Prior systemic or local antitumor therapy for locally advanced esophageal squamous cell carcinoma.
* Systemic non-specific immunomodulatory therapy within 2 weeks prior to randomization.
* Major surgery or severe trauma within 4 weeks prior to randomization.
* Known allergy to any component of the investigational drug(s).
* Active autoimmune disease requiring systemic treatment within 2 years prior to randomization.
* Active hepatitis B infection.
* Known active tuberculosis.
* Severe infections within 4 weeks prior to randomization.
* History of immunodeficiency or positive HIV test.
* Known active syphilis infection.
* Live vaccination within 4 weeks prior to randomization or planned during the study.
* History of allogeneic organ transplantation or hematopoietic stem cell transplantation.
* Is currently participating in a study of an investigational agent or using an investigational device.