Cancer remains one of the leading causes of morbidity and mortality worldwide. Advances in molecular diagnostics have significantly improved cancer detection, monitoring, and treatment personalization. Liquid biopsy has emerged as a revolutionary, minimally invasive diagnostic approach that enables real-time assessment of tumor biology through analysis of circulating tumor-derived components in body fluids, particularly blood. Unlike traditional tissue biopsies, liquid biopsies can be performed repeatedly, allowing dynamic monitoring of disease progression, treatment response, and emergence of resistance mutations. This review explores the role of liquid biopsy in cancer management, focusing on circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), exosomes, microRNAs, and other biomarkers. The article discusses clinical applications in early cancer detection, precision oncology, therapeutic monitoring, minimal residual disease assessment, and future perspectives involving artificial intelligence and multi-omics technologies.