Immunotherapy treatments such as antibodies targeting cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), programmed cell death protein 1 (PD-1) and PD-1 ligand1 (PD-L1) have shown promise in reactivating weakened immune cells to fight cancer. While these immunotherapies have had a dramatic impact in some cancer patients, the positive results only appear in a fraction of cases.
