This is a prospective, multicenter, observational cohort study of patients with esophageal squamous cell carcinoma who have received neoadjuvant immunochemotherapy and are scheduled to undergo curative esophagectomy with standard systematic lymphadenectomy.

The study will not alter the current standard surgical approach. All patients will receive curative esophagectomy and systematic lymph node dissection according to institutional practice. Lymph nodes will be separated and recorded by anatomical station during surgery, followed by station-level pathological assessment. Imaging findings, pathological response, perioperative outcomes, recurrence patterns, disease-free survival, overall survival, and selected immune microenvironment features will be collected and analyzed.

The purpose of this study is to characterize station-level residual lymph node metastasis risk and immune activity after neoadjuvant immunochemotherapy. The findings may help identify candidate lymph node stations for future research on individualized or lymph node-preserving surgical strategies in esophageal squamous cell carcinoma.

Inclusion Criteria:

• Age 18 to 75 years, regardless of sex.
• Eastern Cooperative Oncology Group performance status of 0 to 1.
• Histologically confirmed thoracic esophageal squamous cell carcinoma.
• Received neoadjuvant immunochemotherapy and considered suitable for curative surgery after multidisciplinary team evaluation.
• Clinically resectable locally advanced or locally progressive disease without evidence of distant metastasis.
• Completed preoperative contrast-enhanced computed tomography of the neck, chest, and abdomen. Positron emission tomography-computed tomography and/or endoscopic ultrasound may be performed if clinically available.
• Considered by the investigator to be able to tolerate curative esophagectomy and standard systematic lymphadenectomy.

Exclusion Criteria:

• Non-squamous cell carcinoma histology or concurrent primary malignancy requiring treatment.
• Previous curative surgery for esophageal cancer or previous radiotherapy for the current esophageal lesion.
• Evidence of distant metastasis, unresectable disease, or considered unsuitable for curative surgery after multidisciplinary team evaluation.
• Severe autoimmune disease requiring long-term systemic immunosuppressive therapy.
• Severe cardiac, pulmonary, hepatic, renal, or other major organ dysfunction that prevents surgery or completion of study-related assessments.
• Any other condition that, in the investigator's judgment, makes the participant unsuitable for the study, including poor compliance, inability to complete scheduled follow-up, or inability to provide key study data.

Patients aged 18 to 75 years with histologically confirmed thoracic esophageal squamous cell carcinoma who have received neoadjuvant immunochemotherapy and are scheduled to undergo curative esophagectomy with standard systematic lymphadenectomy at participating centers.