A Trial of SHR-1701 With or Without Chemotherapy in Patients With Stage III NSCLC

Inclusion Criteria: * Voluntarily participate in the study and sign the informed consent form; * 18 to 70 years old, both male and female; * ECOG score: 0-1 * histopathologically or cytologically confirmed, inoperable stage III squamous cell or non-squamous cell lung cancer; * subjects who can provide fresh or archival tumor tissue; * Measurable lesions available; * Major organ function is basically normal; * Non-surgically sterile female subjects of childbearing age must have a negative serum HCG test before randomization; Exclusion Criteria: * histologically or cytologically confirmed mixed SCLC and NSCLC; * subjects who have malignant pleural effusion; * Previous systemic anti-tumor therapy for NSCLC; * Previous thoracic radiotherapy; * Subjects who participated in other clinical trials within 4 weeks or 5 drug half-lives(whichever is shorter) before the first dose. * Systemic immunostimulant therapy before the first dose; * Systemic immunosuppressive therapy before the first dose or were expected to require systemic immunosuppressive drugs during the study treatment; * Subjects with autoimmune diseases; * Other malignant tumors other than non-small cell lung cancer within 5 years before screening; * Known or suspected interstitial pneumonia; * Other moderate to severe lung diseases that may interfere with the detection or treatment of drug-related pulmonary toxicity and seriously affect respiratory function; * Severe cardiovascular and cerebrovascular diseases; * Clinically significant bleeding symptoms or significant bleeding tendency within 1 month before the first dose; * Arteriovenous thrombotic events within 3 months before the first dose; * Positive HIV test; * Active hepatitis B or C; * Evidence of active tuberculosis infection within 1 year before the first dose; * Serious infection within 4 years before the first dose; * History of attenuated live vaccination 28 days before the first dose or expected to receive attenuated live vaccination during the study; * Major surgeries other than diagnosis or biopsy within 28 days prior to first dose; * Previous or planned allogeneic bone marrow transplantation or solid organ transplantation; * History of severe allergic reactions to other monoclonal antibodies/fusion proteins; * Allergic to any component of the randomized treatment regimen; * Female subjects who are pregnant, lactating, or planning to get pregnant during the study period; * Subjects who has a known history of psychotropic drug abuse, alcoholism, or drug abuse * Presence of other conditions that, in the opinion of the investigator, would make participation in this clinical trial inappropriate.