The most advanced and effective approach for early prediction, prevention, and treatment of cancers is predictive, preventive, and personalized medicine, widely known as PPPM or 3P medicines. This is one of the most important and new directions for the treatment of cancer. Lung cancer is a principal cause of cancer mortality globally, of which non-small-cell lung cancer (NSCLC) accounts for more than 85% deaths. Variations in genetic mutations, histological differences, and heterogeneity in gene expression are also linked to lung cancer patients of the same subtype. These variations closely correlate with diverse therapeutic outcomes, often accompanied by resistance and discrepancies in drug response. Therefore, to prevail in the battle against lung cancer, it is essential to identify the precise biomarkers that will unequivocally indicate a patient’s likelihood of responding to chemotherapy. For example, various molecular profiling techniques, including polymerase chain reaction (PCR)-based tests and next-generation sequencing (NGS), help oncologists to identify the key mutation and changes in various important genes such as EGFR, ALK, and ROS1, and can also help to make individualized treatment regime choices. On the plus side, liquid biopsy offers a minimally invasive method of analysing ctDNA for ongoing treatment response monitoring and resistance mutation detection, which further personalizes treatment. In this respect, it may enable health care professionals to formulate and execute a variety of personalized treatment approaches based on the molecular characteristics of a patient’s tumour, which could result in better treatment outcomes with fewer or minor adverse effects compared to regular chemotherapy. So, for the management of NSCLC (i.e. those who are more vulnerable to have significant genetic abnormalities, particularly the patients with adenocarcinoma or non-smokers), the incorporation of molecular diagnostics across clinical practice has grown into a very essential thing. Personalized approaches are given for individualized treatment strategies, considering not only the molecular profile of the tumour but also the patient’s overall health and performance status. Personalized plans for the treatment of individual patients are best when developed by considering not only molecular features of the tumour, but also other implications that involves the patient’s health and functional status. So, in this chapter we would like to discuss the molecular profiling of tumours and their associated different techniques that help us to properly diagnose the type and stage of NSCLC and help in developing targeted therapy and personalized medicine.