A Study to Learn About the Study Medicine Called PF-08634404 in Combination With Chemotherapy in Adult Participants With Locally Advanced or Metastatic Non-Small Cell Lung Cancer

This study is being done to find out if a new medicine called PF-08634404, when given with chemotherapy, works better than the present standard treatment (pembrolizumab with chemotherapy) for adults with a type of lung cancer called non-small cell lung cancer (NSCLC) that is either locally advanced (spread to nearby tissues) or has spread to other parts of the body. To join the study, participants must meet the following conditions: * Be 18 years or older. * Have locally advanced (Stage IIIB/IIIC) or metastatic (Stage IV) squamous or non-squamous NSCLC. * Is not a candidate for complete surgical resection or curative chemoradiotherapy. * Do not have known actionable genomic alterations * Be treatment naïve for advanced or metastatic disease Participants in this study will be assigned to two different parts of the study depending on their type of tumor: participants with squamous NSCLC will be assigned to Part 1, while participants with non-squamous NSCLC will be assigned to Part 2. Each participant will be randomly assigned (like a flip of the coin) to one of two treatment groups in a blinded fashion: * Part 1 - Arm A or Part 2 - Arm C (Experimental Group): Will receive a new study medicine called PF-08634404 along with a kind of chemotherapy specific to the type of tumor. * Part 1 - Arm B or Part 2 - Arm D (Control Group): Will receive an approved medicine called pembrolizumab along with a kind of chemotherapy specific to the type of tumor. Participants will receive their assigned treatment through intravenous (IV) infusions, which means the medicine is given directly into a vein. The treatment will be given in cycles, participants will receive PF-08634404 or Pembrolizumab in combination with chemotherapy followed by maintenance with either PF-08634404 or Pembrolizumab monotherapy (Part 1) or PF-08634404 or Pembrolizumab in combination with a chemotherapeutic drug (Part 2). Participants will continue receiving treatment if it is helping and not experiencing serious side effects. The study will include regular visits for: * Treatment and health checks: while participant continues receiving treatment. * Tests to monitor how cancer responds: every 6 weeks during the first 48 weeks, then every 12 weeks thereafter.