On the other hand, immune checkpoint blockade (ICB) therapy is a promising immunotherapy that works by inhibiting the binding of immune checkpoint proteins, such as cytotoxic T lymphocyte antigen 4 (CTLA-4) and programmed cell death 1 protein (PD-1) on T cells to their ligands, in order to reverse the inactivation and exhaustion of T cell, and thus restore the function of T cells to kill tumor cells. Here, PDCD1 is linked to neoplasm.