Phase 2 Platform Study of Novel Immunotherapy Combinations in Participants with Previously Untreated, Advanced/Metastatic Non-Small-Cell Lung Cancer

INTERVENTION: Drug: Dostarlimab Dostarlimab will be administered. Drug: GSK4428859A GSK4428859A will be administered. Drug: GSK6097608 GSK6097608 will be administered. Drug: Pembrolizumab Pembrolizumab will be administered. CONDITION: Non‐small cell lung cancer PRIMARY OUTCOME: To evaluate the antitumor activity of novel immunotherapy combinations compared with pembrolizumab in participants with PD‐L1‐high (TC/TPS>=50%) NSCLC SECONDARY OUTCOME: ‐To assess the dose‐response relationship of novel immunotherapy combinations across a range of the novel components' dose levels and fixed dostarlimab dose (may not apply to all novel combinations); ‐To further assess the clinical activity of novel immunotherapy combinations compared with pembrolizumab in participants with PD‐L1‐high (TC/TPS>=50%) NSCLC; ‐To evaluate the antitumor activity of novel immunotherapy combinations via treatment arm comparisons for assessment of contribution of components for the combination regimens; ‐To further characterize the safety of novel immunotherapy combinations; ‐To determine the immunogenicity of individual agents comprising novel immunotherapy combinations; ‐To characterize the PK properties of novel immunotherapy combinations INCLUSION CRITERIA: Participant must be more than or equal to (>=)18 years of age. Has a histologically or cytologically confirmed diagnosis of locally advanced unresectable NSCLC not eligible for curative surgery and/or definitive radiotherapy with or without chemotherapy or metastatic NSCLC (squamous or nonsquamous). Has not received prior systemic therapy for their locally advanced or metastatic NSCLC. Provides a tumor tissue sample obtained at the time of or after the initial diagnosis of locally advanced or metastatic NSCLC. Has a PD‐L1‐high (TC/TPS‐50%) tumor as determined by the DAKO 22C3 or VENTANA SP263 assay performed by a local laboratory or by the VENTANA SP263 assay at a central laboratory. Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0‐1. Adequate organ function per protocol specifications. Male or female participants. Female participants are eligible to participate if they are not breastfeeding or pregnant (or intend to brea