Researchers have found that immune cells can be programmed within the body to fight cancer, with some studies suggesting the creation of engineered "natural killer" cells to combat the disease. A potential therapy is being tested in a clinical trial, although it is unclear what methods or substances are being used to program these cells. The relationship between immune cells and cancer treatment is still being explored, with some findings indicating that certain factors, such as immunotherapy, may have limited effects on certain immune cells.