PDCD1 and neoplasm: Combining CTLA-4 and PD-1, ICIs with tumor infiltrating lymphocytes, anti-PD-1 with low-dose cyclophosphamide, ICIs with CAR-T cells or bispecific T-cell engager antibodies, or ICIs with dendritic cell vaccines are possibilities for increasing the efficacy of immune-mediated anti-tumor response through immune modulation of different pathways and at different levels [98].