ILC1, or Innate Lymphoid Cell 1, is a type of immune cell that plays a crucial role in the body's defense system. These cells are part of the innate immune response, which means they act quickly to help protect the body from infections and diseases. ILC1 cells are particularly important for fighting off viral infections and certain types of tumors. These cells are found in various tissues, including the lungs and gut, where they help maintain a balance in the immune system. By producing specific signaling molecules called cytokines, ILC1 cells can communicate with other immune cells, enhancing the body's ability to respond to threats effectively.