• Having sufficient understanding of this study and being willing to sign the informed consent form (ICF).

• Males or females, age 18-75 years at the time of signing the informed consent form.

• Histologically or cytologically confirmed, unresectable locally advanced and metastatic non-small cell lung cancer not suitable for radical concurrent chemoradiotherapy.

• Without known EGFR mutation/ALK fusion/ROS1 fusion gene.

• Previous failed concurrent or sequential treatment with systemic platinum-containing chemotherapy and PD-1/PD-L1 inhibitor therapy for NSCLC that cannot be radically resected or not suitable for radical concurrent radio chemotherapy.

• Five consecutive unstained slides from formalin-fixed paraffin-embedded (FFPE) tumor tissue (archived tumor tissue up to 5 years or freshly biopsied tumor tissue) sources are available for PD-L1 testing in the central laboratory.

• PD-L1 TPS ≥50% by 22C3 antibody IHC assay in the central laboratory.

• At least one measurable lesion (in accordance with RECIST v1.1).

• Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 or 1.

• Estimated life expectancy of at least 3 months.

• Adequate hematologic, hepatic, renal and coagulation function as defined per protocol.

• Male and female subjects of childbearing potential must be willing to be completely abstinent or to use a highly effective method of contraception (i.e., a failure rate of less than 1%) from the time of signing the informed consent form until 3 months after the last dose of study drug.