A Multicenter, Randomized, Open-Label, Phase 1b/2 Trial Of Valemetostat Tosylate Plus Pembrolizumab Vs Pembrolizumab Alone in Participants With Advanced or Metastatic Non-Small Cell Lung Cancer Whose Tumors Express PD-L1 With Tumor Proportion Score ≥50% Without Actionable Genomic Alterations

Key Inclusion Criteria: 1. Has signed and dated the ICF, prior to the start of any trial-specific qualification procedures. 2. Is an adult ≥18 years of age or the minimum legal age (whichever is greater) at the time of informed consent. (Follow local regulatory requirements if the legal age of adult voluntary consent for trial participation is \>18 years old). 3. Has histologically documented NSCLC that meets all of the following criteria: 1. Has no prior systemic therapy for advanced or metastatic disease. 2. Has Stage IIIB or IIIC disease and is not a candidate for surgical resection…