The purpose of this study is to evaluate the progression-free survival (PFS) of Chemotherapy combined with SHR-1316 in patients with advanced esophageal squamous cell cancer.

Inclusion Criteria:

1. Histologically or cytologically confirmed unresectable local advanced/recurrent or metastasis esophageal squamous cell carcinoma;
2. No previous systemic anti-tumor treatment;
3. Subjects must have at least one measurable tumor lesion per RECIST 1.1;
4. ECOG: 0-1;
5. Adequate organ and bone marrow function;

Exclusion Criteria:

1. Allergic to monoclonal antibodies, any SHR-1316 components,Irinotecan , Fluorouracil ;

2. Prior therapy as follow:

   1. Anti-PD-1 or anti-PD-L1;
   2. Any experimental drugs within 4 weeks of the first dose of study medication;
   3. Received major operations or serious injuries within 4 weeks of the first dose of study medication;
   4. Received last dose of anticancer therapy (including chemotherapy, radiotherapy, targeted therapy, etc.) within 4 weeks of the first dose of study medication;

3. Not recovered to ≤CTCAE 1 from adverse events (except for hair loss) due to a previously anti-tumor treatment;

4. Subjects with any active autoimmune disease or history of autoimmune disease;

5. Pregnancy or breast feeding;