Elevated copper levels induce tumor cuproptosis and ferroptosis, leading to immunogenic cell death and subsequent antitumor immune responses. However, dysregulated copper metabolism in tumor cells maintains homeostatic copper balance, while hypoxic microenvironments hinder therapeutic efficacy. In this study, we present a nanozyme system, termed CussOMEp, comprising a copper-based nanovector (CussNV) that is PEGylated and loaded with omeprazole, a copper transporter inhibitor, to enhance tumor synergistic immunotherapy by promoting cuproptosis and ferroptosis. CussNV is assembled from dithiodiglycolic acid and copper ions, exhibiting peroxidase, glutathione oxidase, and catalase-like activities, along with responsive degradability. This nanozyme alleviates tumor hypoxia by producing oxygen, induces ferroptosis through the generation of lethal hydroxyl radicals, and depletes glutathione. Additionally, omeprazole increases cellular copper concentration and oxidative stress by inhibiting the intracellular copper-transporting ATPase 1 (ATP7A), enhancing lipoylated protein oligomerization and cuproptosis. In a breast tumor mouse model, CussOMEp elicits robust antitumor immune responses, including dendritic cell maturation and T cell proliferation. When combined with PD-1 antibodies (αPD-1), CussOMEp significantly inhibits tumor metastasis in bilateral and lung metastatic models. This work presents a functional nanozyme system as a promising strategy for synergistic tumor immunotherapy leveraging ferroptosis and cuproptosis.