Explore the efficacy and safety of Envafolimab in first line treatment of elderly patients with locally advanced or metastatic non-small cell lung cancer with high PD-L1 expression, view to providing better treatment options for elderly patients with high PD-L1 expression and improving the survival and prognosis of patients .

Inclusion Criteria:

• Signed written informed consent.
• Age strictly at least 70 years.
• Cytologically or histologically proven NSCLC(adenocarcinoma, epidermoid carcinoma, large-cell carcinoma) of locally advanced (stage IIIb/IIIc), metastatic, or relapsing (stage IV) according to the American Joint Committee on Cancer Staging Handbook.
• Presence of at least one measurable target lesion (RECIST rules) in a non irradiated region.
• No previous systemic chemotherapy for lung cancer.
• PD-L1≥50% in tissue samples detected by immunohistochemistry.
• PS 0 or 1.
• Life expectancy sup 12 weeks.
• Normal hematologic function.

Exclusion Criteria:

• EGFR-sensitive mutations or ALK rearrangements
• Previous treatment with immune checkpoint inhibitors
• Presence of symptomatic brain metastases；
• Chinese patent medicine with anti-lung cancer indications or immunoregulatory drugs (including thymopeptide, interferon and interleukin, except for the local use of pleural effusion control) for systemic treatment；
• Another previous or concomitant cancer, except for basocellular cancer of the skin or treated cervical cancer in situ；
• Concurrent administration of one or several other antitumor therapies；
• Concurrent participation in another clinical trial；
• Active autoimmune disease requiring systemic treatment occurred within 2 years prior to initial；
• Systemic glucocorticoid therapy or any other form of immunosuppressive therapy within 7 days prior to initial administration；
• Contraindication to the study drugs；
• Has not fully recovered from toxicity and/or complications caused by any intervention prior to the commencement of treatment (i.e., grade 1 or baseline, excluding fatigue or hair loss);
• A history of human immunodeficiency virus (HIV) infection;
• Untreated active hepatitis B (defined as HBsAg positive and HBV-DNA copy number detected greater than the upper limit of normal value in the laboratory of the research center);
• Active HCV infected;
• Recent vaccination within 30 days before the first administration (cycle 1, day 1);
• Other severe concurrent disorders that occurred during the prior six months before enrollment (myocardial infection, severe or unstable angor, NYHA class 3 or 4 congestive heart failure, transient or constituted cerebral ischemic attack, psychiatric or neurological disorders preventing the patient from understanding the trial, uncontrolled infections).