A new line of cancer immunotherapy research centers on restoring immune “gatekeeper” function. In a Science study, researchers at St. Jude Children’s Research Hospital reported that tumors can disrupt dendritic cells’ mitochondrial function, impairing the antigen presentation needed to kick off anti-tumor immunity. The work identifies a mechanistic route to counteract that suppression by reprogramming how dendritic cells handle mitochondria under tumor pressure—an approach that could inform next-generation combinatorial strategies with existing immunotherapies.