A Study to Compare Ociperlimab Plus Tislelizumab Versus Durvalumab Following Concurrent Chemoradiotherapy (cCRT) in Participants With Stage III Unresectable Non-Small Cell Lung Cancer

Key Inclusion Criteria:

1. Age ≥ 18 years on the day of signing the informed consent form (or the legal age of consent in the jurisdiction in which the study is taking place).
2. Participant has histologically or cytologically confirmed, locally advanced, unresectable Stage III NSCLC (AJCC Cancer Staging Manual 2017, derived from IASLC) prior to initiation of cCRT.
3. Participant must have completed at least 2 cycles of platinum-based chemotherapy concurrent with radiotherapy
4. Participants must have not experienced PD following definitive, platinum-based cCRT.
5. Eastern Co-operative Oncology Group (ECOG) Performance Status of 0 or 1.
6. Participants must have adequate organ function
7. Agree to provide archival tissue (formalin-fixed paraffin-embedded block containing tumor \[preferred\] or approximately 6 to 15 freshly cut unstained slides) or fresh biopsy obtained prior to cCRT (if archival tissue is not available) for prospective central evaluation of PD-L1 levels and retrospective analysis of other biomarkers.

Key Exclusion Criteria:

1. Prior therapy with an anti-PD-1, anti-PD-L1, anti-PD-L2, TIGIT, or any other antibody or drugs specifically targeting T-cell co-stimulation or checkpoint pathways.
2. Diagnosed with NSCLC that harbors an epidermal growth factor receptor (EGFR) sensitizing mutation, anaplastic lymphoma kinase (ALK) gene translocation, ROS1 gene translocation or RET gene rearrangement.
3. Participants who received systemic anticancer treatment besides the specified cCRT.
4. Any unresolved toxicity CTCAE \> Grade 2 from the prior cCRT.
5. Active autoimmune diseases or history of autoimmune diseases that may relapse.
6. Any condition that required systemic treatment with either corticosteroids (\> 10 mg daily of prednisone \[in Japan, prednisolone\] or equivalent) or other immunosuppressive medication ≤ 14 days before the first dose of study treatment.
7. Infection (including tuberculosis infection, etc) requiring systemic antibacterial, antifungal, or antiviral therapy within 14 days before the first dose of study treatment.

Note: Antiviral therapy is permitted for participants with chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection.

NOTE: Other protocol Inclusion/Exclusion criteria may apply.