This study collects stool, blood, and tumor tissue samples from patients with locally advanced esophageal cancer after receiving Sintilimab and chemotherapy to explore the efficacy and intestinal microbes of chemotherapy combined with neoadjuvant immunotherapy for locally advanced operable thoracic esophageal squamous cell carcinoma The main purpose is the relationship between its metabolites, and it will also explore the changes of intestinal flora diversity and metabolites before and after esophageal squamous cell carcinoma chemotherapy combined with immune neoadjuvant therapy

Inclusion Criteria:

• 1) Age ≥18 years old and ≤75 years old; 2) Patients with stage I~III thoracic esophageal squamous cell carcinoma diagnosed by histopathological examination (excluding mixed adenosquamous carcinoma and other pathological types); 3) ECOG PS score is 0 or 1; 4) It has sufficient organ and bone marrow function.

Exclusion Criteria:

1. Refuse to participate;
2. Patients who have a higher risk of bleeding or perforation due to the tumor's obvious invasion of the adjacent organs (aorta or trachea) of the esophageal lesion, or patients who have formed a fistula;
3. Have previously received anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CD137 or anti-CTLA-4 antibody therapy, or any other antibodies targeting T cell costimulation or checkpoint pathways as specific targets or drug;
4. Participate in another interventional clinical study at the same time, unless participating in an observational (non-interventional) clinical study or in the follow-up phase of an interventional study;
5. Have received systemic systemic treatment with anti-tumor indications Chinese herbal medicine or immunomodulatory drugs (including thymosin, interferon, interleukin, etc.) within 2 weeks before the first administration;
6. Have used immunosuppressive drugs within 1 week before enrollment, excluding nasal spray, inhalation or other local glucocorticoids or physiological doses of systemic glucocorticoids (ie no more than 10mg/day prednisone Or equivalent doses of other glucocorticoids), or use hormones to prevent allergy to contrast agents.