The novel CPP-IL-12 demonstratedan increase in IL-12 levels in melanoma cells and promoted immunotherapyfor melanoma by stimulating immunogenic cell death CD4+ T cells andimproving the activity of tumor-targeting CD8+ T cells, demonstratingCPP-IL-12 potential for tumor treatment.83 In another research project, Zhao et al. developed a CaCO3 NP coated with a cancer cell membrane modified with cyclic arginyl-glycyl-asparticacid peptide (cRGD) to deliver IL-12 messenger ribonucleic acid (mRNA).These NPs can acquire the ability to cross the blood-brain barrierand target brain tumors effectively. Here, CD4 is linked to melanoma.