Moreover, Met@Man-MPs significantly enhanced the numbers of CD8+ T cells (Fig. 4f), activated CD8+CD69+ T cells (Fig. 4g), CD4+ T cells (Fig. 4h), and activated CD4+CD69+ T cells (Fig. 4i), while markedly decreased the numbers of MDSCs (Fig. 4j) and Tregs (Fig. 4k) in tumor tissues compared with free Met, Met@MPs and even high dosage of Met. Here, CD69 is linked to neoplasm.