This study is being conducted to explore the efficacy of SHR-6390 and SHR-1020 in the treatment of esophageal squamous cell carcinoma after progression on PD-1 Antibody.

Inclusion Criteria:

• Patients who were diagnosed as esophageal squamous cell carcinoma by histopathology with at least one measurable lesion according to RECIST 1.1 criteria.
• Must have had progressive disease after previous treatment with PD-1 inhibitor
• ECOG score 0-2
• The expected survival time is ≥ 12 weeks
• Previous permanent discontinuation did not occur due to adverse events associated with immunotherapy, or the immunotreatment-related adverse events recovered to ≤1 grade

Exclusion Criteria:

• Had other active malignant tumors within 5 years before entering the study
• Had abnormal swallowing function or dysfunction of gastrointestinal absorption
• The first study drug treatment was less than 28 days or 5 half-lives (in terms of longer) from the last radiotherapy, chemotherapy, targeted therapy or immunotherapy
• Patients who have already received surgery within 28 days (biopsy for diagnosis is permitted)
• Pregnant or lactating women