Anti-CTLA-4 activates Treg cells (Tregs), which suppress dendritic cells (DCs) in lymph nodes, and simultaneous anti-PD-1 treatment inhibits effector T cell (Teff) and natural killer cell (NK) activation in peripheral tissues, inducing regulatory T cell (Treg) differentiation, meanwhile facilitating anti-tumour response rates. This evidence concerns the gene PDCD1 and neoplasm.