A combination of PD‑1/PD‑L1 inhibitors: The prospect of overcoming the weakness of tumor immunotherapy (Review).

Programmed cell death protein‑1 (PD‑1)/programmed death protein ligand‑1 (PD‑L1) inhibitors for treatment of a various types of cancers have revolutionized cancer immunotherapy. However, PD‑1/PD‑L1 inhibitors are associated with a low response rate and are only effective on a small number of patients with cancer. Development of an anti‑PD‑1/PD‑L1 sensitizer for improving response rate and effectiveness of immunotherapy is a challenge. The present study reviews the synergistic effects of PD‑1/PD‑L1 inhibitor with oncolytic virus, tumor vaccine, molecular targeted drugs, immunotherapy, chemotherapy, radiotherapy, intestinal flora and traditional Chinese medicine, to provide information for development of effective combination therapies.