Nature Communications, Published online: 14 September 2026; doi:10.1038/s41467-026-76657-3 Histone H3K36 methyltransferases are frequently altered in cancer, yet the distinct roles of H3K36 methylation states in tumorigenesis and immunity remain unclear. This study identifies an H3K36-dependent epigenetic circuit that controls endogenous retroviral elements (ERVs) repression and immune surveillance in KRAS-driven lung cancer models.