PDCD1 and neoplasm: Curran et al. [124] designed mouse models to show that the vaccine secreting granulocyte/macrophage-colony stimulating factor (GM-CSF) or Flt3-ligand, combined with PD-1 and CTLA-4 blocking therapy, can effectively prolong the survival period and improve the ratio of effector cells to regulatory cells in the tumor microenvironment of mice.