CRISPR-Cas9 is a gene-editing technology that allows scientists to modify DNA. It has opened new possibilities in biology and genetics by allowing humans to modify or analyze DNA more deeply. The purposes of CRISPR include extending lifespan by modifying DNA to protect cells from viruses and diseases, improving quality of life. Scientists have used CRISPR to effectively manipulate Cas9 and achieve things in genetics, medicine, and agriculture, such as changing butterfly colors, curing mice of liver diseases, and discovering relationships between animal and human diseases. CRISPR has expanded human understanding by enabling precise genetic manipulation and providing new insights into living things.