CD4 and neoplasm: Combined with DPPA-1 peptide-mediated anti-PD-L1 therapy, it alleviates T cell inhibition, increases CD4+ and CD8+ T cells (by 2.18% and 3.57%, respectively), reduces myeloid inhibitory cells, achieves a tumor inhibition rate of 67.9%, significantly inhibits tumor growth, and prevents metastasis, demonstrating the potential of nano-SDT synergistic checkpoint inhibition.