Élie Metchnikoff was a Russian zoologist and microbiologist, best known for his pioneering work in immunology. He discovered the process of phagocytosis, where certain cells in the body engulf and digest harmful microorganisms. This groundbreaking research laid the foundation for understanding how the immune system protects the body from infections. In 1908, Metchnikoff was awarded the Nobel Prize in Physiology or Medicine for his contributions to the field of immunology. His work not only advanced scientific knowledge but also influenced the development of vaccines and treatments for various diseases, highlighting the importance of the immune response in health.