How did edward Jenner find cure for smallpox?

Edward Jenner discovered the cure for smallpox through his observation that milkmaids who had contracted cowpox, a less severe disease, seemed to be immune to smallpox. In 1796, he tested his hypothesis by inoculating a young boy with cowpox and later exposing him to smallpox, finding that the boy did not develop the disease. This pioneering work led to the development of the smallpox vaccine, which ultimately contributed to the eradication of the disease. Jenner's method laid the groundwork for modern immunology and vaccination practices.