SHR-1316 Combined With Chemotherapy and Chest Radiotherapy in ES-SCLC

Inclusion Criteria: * Confirmed diagnosis of Extensive small cell lung cancer * Eastern Cooperative Oncology Group performance status (PS) of 0 to 1 * 18 to 75 years old * The function of vital organs meets the following requirements. WBC ≥ 3.0 × 10\^9/L, ANC≥1.5×10\^9/L, PLT≥100×10\^9/L, Hb≥9g/dL, ALT and AST ≤2.5 times ULN, TBIL ≤1.5 x ULN, CREA ≤1.5 times ULN or CCr≥50mL/min. INR≤1.5 x ULN, APTT ≤1.5 x ULN * have not received first-line systemic therapy or immunosuppressive therapy for es-sclc * The estimated survival period is more than 8 weeks * With measurable lesion defined by the RECIST v1.1: Previously irradiated lesions may only be considered as measurable disease if disease progression has been unequivocally documented at that site since radiation and the previously irradiated lesion is not the only site of disease; * Signed written informed consent prior to study entry Exclusion Criteria: * Active or untreated CNS metastases * Leptomeningeal diseases * Uncontrolled or symptomatic hypercalcemia * Active, known or suspected autoimmune diseases * have received any T cell co stimulation or immune checkpoint therapy * Corticosteroids (\> 10 mg / day prednisone or equivalent) or other immunosuppressants were used within 14 days before the first dose of study drug. * Subjects had active infections. * Failing to properly control the clinical symptoms or disease of the heart * Patients who have previously received allogeneic bone marrow transplantation or solid organ transplantation * Known to be allergic to the study drug or excipients, known to have a serious allergic reaction to any kind of monoclonal antibody; have a history of hypersensitivity to cisplatin or etoposide * According to the researcher's judgment, there are other factors that may lead to the termination of the study