Cancer immunotherapy has been a game-changer, but many tumors still find ways to slip past the immune system. New research reveals a hidden trick: cancer cells can package the immune-blocking protein PD-L1 into tiny particles that circulate through the body and weaken immunotherapy’s impact. Scientists in Japan discovered that a little-known protein, UBL3, controls this process—and surprisingly, common cholesterol-lowering drugs called statins can shut it down.