Lung cancer is a serious global health problem as it is the leading cause of cancer death worldwide. Early detection of lung cancer is key to improving patient prognosis. Unfortunately, early diagnosis is often challenging due to the non-specific symptoms that patients may experience in the early stages of the disease. Most patients are therefore diagnosed at an advanced stage, which significantly reduces the chances of a cure. However, thanks to advances in molecular profiling of cancer, the possibility of a personalized approach to treatment is opening up. Key mutations have been identified, such as those on epidermal growth factor receptors (EGFR), which play an important role in the development of non-small cell lung cancer (NSCLC). The discovery of EGFR tyrosine kinase inhibitors (TKIs) has been a breakthrough in the treatment of NSCLC, as this targeted therapy improves patients' quality of life, reduces side effects and prolongs progression-free survival. While they have revolutionized the treatment of NSCLC, it is not uncommon for patients to develop resistance to EGFR-TKIs. However, new research and new technologies are opening up the way to understanding the mechanisms of resistance and developing new therapeutic strategies, offering hope that future outcomes for all patients battling this difficult disease will be improved.