Liquid biopsy is a minimally invasive diagnostic tool for cancer that analyzes easily accessible fluids such as blood, urine, and cerebrospinal fluid for cancer-specific biomarkers. It provides real-time information on tumor progression and treatment response and has several advantages over tissue biopsy. Technological improvements and standardization are expected to make it widely available at affordable prices, potentially reducing cancer mortality and contributing to achieving Sustainable Development Goal 3 (SDG 3). While further advancements are needed to make it affordable, liquid biopsy has the potential to revolutionize the diagnosis and treatment of cancer globally, benefitting both high- and lower-income populations. Its immense potential can reduce the burden of cancer and improve health outcomes for all.