A Study of TQB2450 in Subjects With Stage III Non-Small Cell Lung Cancer(NSCLC)

Inclusion Criteria: 1. 18-75 years old ; Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1; Life expectancy ≥ 3 months. 2. Histologically or cytologically confirmed unresectable (Stage III) Non-Small Cell Lung Cancer. 3. At least has one measurable lesion before radiotherapy. 4. At least has one type of platinum-containing chemotherapy, Absence of progression after concurrent/sequential chemoradiotherapy. 5. Adequate laboratory indicators. 6. No pregnant or breastfeeding women, and a negative pregnancy test. 7. Understood and signed an informed consent form. Exclusion Criteria: 1. Squamous cell carcinoma meets following conditions should be excluded: 1. Cavernous lung cancer. 2. Has hemoptysis and maximum daily hemoptysis volume ≥ 2.5ml within 1 month before the first administration. 2. Has received anti-angiogenic drugs or other PD-1 / PD-L1 / CTLA-4 antibody therapy or other immunotherapy against PD-1 / PD-L1 / CTLA-4. 3. Severe hypersensitivity occurs after administration of other monoclonal antibodies. 4. Diagnosed and/or treated additional malignancy within 5 years with the exception of cured basal cell carcinoma of skin ,carcinoma in situ of prostate,and carcinoma in situ of cervix. 5. Pathologically confirmed mixed small cell and non-small cell lung cancer. 6. EGFR gene mutations. 7. Has any active autoimmune disease or history of autoimmune disease. 8. After the early stage of chemoradiotherapy, the treatment toxicity ≥ grade 2 is not fully alleviated. 9. Has ≥grade 2 pneumonia. 10. Immunosuppressant or systemic or absorbable local hormone therapy is required to achieve the aim of immunosuppression (dose \> 10mg/ day prednisone or other therapeutic hormones) and is still used within 2 weeks after the first administration. 11. Has multiple factors affecting oral medication. 12. Has active bleeding or a persistent decrease in hemoglobin. 13. Has any bleeding or bleeding events ≥grade 3 in the first 4 weeks before the first administration. 2.Has received anti-angiogenic drugs or other PD-1 / PD-L1 / CTLA-4 antibody therapy or other immunotherapy against PD-1 / PD-L1 / CTLA-4. 14\. Has unhealed wounds, fractures, active gastric and duodenal ulcers, positive continuous fecal occult blood, ulcerative colitis in the first 4 weeks before the first administration. 15\. Has received NMPA approved anti-tumor drugs or immunomodulatory drugs for systemic treatment within 2 weeks before the first administration. 16.Has a history of a hematological system transplantation or organ transplantation. 17\. Has active diverticulitis、peritoneal abscess, intestinal obstruction. 18. Has any serious and/or uncontrollable disease. 19. According to the judgement of the investigators, there are other factors that may lead to the termination of the study.