Clinical Trial Evaluating the Safety and Efficacy of Chemoimmunotherapy Plus Short Course of Mek Inhibitor in First Line of Treatment of Metastatic Non Squamous Non Small Cell Lung Adenocarcinoma With PDL1 < 50 %.

This study is testing a combination of chemotherapy, immunotherapy, and a short course of a targeted drug (MEK inhibitor) as a first-line treatment for advanced non-small cell lung cancer where the tumor has low levels of a protein called PD-L1. **You may be eligible if...** - You are 18 or older with advanced (metastatic) non-squamous non-small cell lung adenocarcinoma (a type of lung cancer) - Your tumor has PD-L1 expression less than 50% - Your tumor does not have EGFR or ALK gene mutations - You have not received prior chemotherapy or immunotherapy for this cancer - You are in good enough general health to tolerate treatment **You may NOT be eligible if...** - You have active brain metastases (cancer spread to the brain) that are untreated - You have autoimmune conditions requiring ongoing treatment - You have had prior treatment with MEK inhibitors or similar targeted therapies - You have certain heart conditions or other serious uncontrolled illnesses Talk to your doctor to see if this trial is right for you.