Biomarkers and Liquid Biopsy are powerful tools in modern cancer detection, monitoring, and treatment personalization. Biomarkers are measurable indicators found in blood, tissues, or other body fluids that provide information about biological conditions, including the presence and progression of cancer. They help in early diagnosis, predicting treatment response, and tracking disease recurrence. Liquid biopsy is a minimally invasive method that detects cancer-related biomarkers such as circulating tumor DNA (ctDNA), RNA, proteins, or exosomes directly from blood or other bodily fluids. Unlike traditional biopsies, liquid biopsies pose less risk and can be performed repeatedly, offering real-time insights into tumor dynamics. These techniques are transforming oncology by enabling early detection, monitoring treatment effectiveness, and guiding personalized therapies, ultimately improving patient outcomes and reducing reliance on invasive procedures.