CD8A and neoplasm: Next, we investigated the infiltration and activation of CD8+ T cells, which directly mediate tumor cell killing.[30] The Cu2O@EG + MW treatment markedly increased CD8+ T cell infiltration, raising the percentage from 2.7% in the PBS group to 26.0%, significantly surpassing the 5.19% observed in the Cu2O@EG groups (Figure 7d,e; Figure S40, Supporting Information).