PIK3CD and cancer: Although cancer is a genetic disease characterized by abnormal cell proliferation, it is also a chronic immune disease.238 Immunotherapy has recently attracted increasing attention and has indeed achieved some progress in treating cancer.238 Studies on the PI3K/Akt signaling pathway in immune cells have shown that its activation is not based on a simple on/off mechanism239; as cancer is a chronic immune disease, immunotherapies should be designed to increase the ability of immune cells to kill tumor cells such that the body exerts a direct antitumor effect.