PDCD1 and cancer: A multitude of clinical trials have been carried out to investigate recombinant IL-15 as a potential therapeutic agent as monotherapy or in combination with other agents in patients with various types of cancer.28, 29, 30, 31, 32 Findings of these studies would provide additional information on the approach of developing anti-PD-1/PD-L1 antibody-IL-15 as a cancer therapeutic agent.