Given that CD8+ T cells could induce tumor cells’ lipid peroxidation and ferroptosis in tumor microenvironment, this study shows a novel insight that L-THP synergizes cytotoxic CD8+ T cell-mediated GC antitumor response and ferroptosis through FSP1 pathway, providing potent evidence for GC immunoregulation. The gene discussed is CD8A; the disease is neoplasm.