In the long search for ways to help the immune system overcome cancer, researchers at UCLA have found an unexpected ally in creatine — a supplement long associated with athletic performance. Their work reveals that creatine does not merely energize the soldiers of the immune system, the killer T cells, but also sustains the generals who direct them: dendritic cells. At a moment when cancer immunotherapy still fails the majority of patients, this discovery opens a quiet but consequential door — one that clinical trials will now be asked to push open.