Lung cancer is the leading cause of cancer-related deaths globally, with over 1.8 million fatalities annually. A major challenge is late-stage diagnosis, limiting treatment options and survival rates. Minimal residual disease (MRD), referring to lingering tumor cells post-treatment, poses a significant risk for recurrence or metastasis. Early MRD detection is crucial for timely intervention and personalized therapy. Liquid biopsy emerges as a revolutionary, non-invasive method for MRD detection by analyzing circulating tumor DNA (ctDNA) in blood. This approach surpasses traditional imaging in sensitivity, enabling early relapse prediction and better patient stratification. Additionally, it facilitates personalized treatment adjustments and advances cancer research by improving clinical trial designs. Despite its promise, liquid biopsy faces challenges such as sensitivity limitations, assay standardization issues, and high costs. Continued research and innovation are necessary to enhance accuracy and accessibility. Integrating liquid biopsy into clinical practice could revolutionize lung cancer management, leading to earlier interventions, improved survival rates, and a new era of precision oncology. This paper highlights the critical role of MRD detection and advocates for the adoption of liquid biopsy as a transformative tool in lung cancer treatment.