On an orthotopic liver cancer model, piezoelectrocatalytically generated H2 and simultaneous LA deprivation co‐activated tumor immunity by liberating effector CD8+ T (TCD8+) cells from the immunosuppression of tumor cells and by inhibiting regulatory T (Treg) cells, respectively (Figure1), achieving highly efficient immunotherapy of liver cancer. The gene discussed is CD8A; the disease is neoplasm.