This review discusses the advancements and challenges in personalized medicine, with a particular focus on pharmacogenomics, which tailors drug therapies to individual genetic profiles. Personalized healthcare utilizes various personal traits-such as age, sex, and socioeconomic status-to enhance disease prevention and treatment. Recent developments in genomics have improved the ability to customize medications for specific patient categories or individuals. The review emphasizes the importance of understanding both the patient's and tumor's genomes in cancer treatment, as this knowledge can optimize drug selection and dosage, potentially reducing side effects compared to traditional chemotherapy. Despite the promise of pharmacogenomic testing, its widespread adoption faces barriers, including financial constraints and insurance coverage issues. The review advocates for preemptive pharmacogenomic testing, which can be more cost-effective and beneficial over a patient's lifetime, and suggests integrating these findings into electronic health records to maximize clinical utility.