A Study of Calderasib (MK-1084) Plus Pembrolizumab (MK-3475) in Participants With KRAS G12C Mutant Non-small Cell Lung Cancer (NSCLC) With Programmed Cell Death Ligand 1 (PD-L1) Tumor Proportion Score (TPS) ≥50% (MK-1084-004/KANDLELIT-004)

The main inclusion and exclusion criteria include but are not limited to the following:

Inclusion Criteria:

* Has histologically or cytologically confirmed diagnosis of non-small cell lung cancer (NSCLC)
* Has newly diagnosed Stage IIIB/IIIC NSCLC, not eligible for curative resection or curative chemotherapy/radiation as determined by a multidisciplinary tumor board and/or by radiation oncologist, surgeon, and medical oncologist or Stage IV (M1a, M1b, or M1c) by American Joint Committee on Cancer (AJCC) Staging Manual, Version 8
* Provides an archival tumor tissue sample (≤5 years) or newly obtained core, incisional, or excisional biopsy of a tumor lesion not previously irradiated to enable central laboratory testing of kirsten rat sarcoma (KRAS) G12C mutation status, PD-L1 status, and biomarker research
* If have had adverse events (AEs) due to previous anticancer therapies, must have recovered to \< Grade 1 or baseline
* If human immunodeficiency virus (HIV)-infected, must have well controlled HIV on antiretroviral therapy (ART)
* If Hepatitis B surface antigen (HBsAg) positive, have received Hepatitis B Virus (HBV) antiviral therapy for at least 4 weeks, and have undetectable HBV viral load
* If a participant has a history of Hepatitis C virus (HCV) infection, HCV viral load is undetectable

Exclusion Criteria:

* Has diagnosis of small cell lung cancer. For mixed tumors, if small cell elements are present, the participant is ineligible
* Has active inflammatory bowel disease requiring immunosuppressive medication or previous clear history of inflammatory bowel disease
* Has known history of, or active, neurologic paraneoplastic syndrome
* Has an active infection requiring systemic therapy, with exceptions
* Has uncontrolled, significant cardiovascular disease or cerebrovascular disease
* Has one or more of the following ophthalmological findings/conditions: intraocular pressure \>21 mmHg and/or any diagnosis of glaucoma, diagnosis of central serous retinopathy, retinal vein occlusion, or retinal artery occlusion, diagnosis of retinal degenerative disease
* Has received prior systemic anticancer therapy for their locally advanced or metastatic NSCLC
* Has received radiation therapy to the lung that is \>30 Gray within 6 months of start of study intervention
* Has received radiotherapy within 2 weeks of start of study intervention. Participants must have recovered from all radiation-related toxicities, not required corticosteroids, and not have had radiation pneumonitis
* Has known active central nervous system metastases and/or carcinomatous meningitis
* Known additional malignancy that is progressing or has required active treatment within the past 3 years
* Has active autoimmune disease that has required systemic treatment in the past 2 years
* Has history of (noninfectious) pneumonitis/interstitial lung disease that required steroids or has current pneumonitis/interstitial lung disease
* Is HIV-infected and has a history of Kaposi's sarcoma and/or Multicentric Castleman's Disease
* Has history of allogenic tissue/solid organ transplant
* Has not fully recovered from any effects of major surgical procedure