In this review study, we focus on the available data regarding the prognostic value of ctDNA in patients with NSCLC who carry druggable genetic driver mutations in significant genes, such as epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), c-ros oncogene 1 (ROS1), rearranged during transfection (RET), Kirsten rat sarcoma virus (KRAS), B-Raf proto-oncogene (BRAF), and mesenchymal–epithelial transition (MET). The gene discussed is KRAS; the disease is non-small cell lung carcinoma.