An Exploratory Clinical Study of SHR6390 and SHR1020 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