PDCD1 and cancer: In the same year, James P. Allison and Tasuku Honjo were honored by the 2018 Nobel Prize in Physiology or Medicine for their discoveries of cancer immunotherapy via the use of antibody blockade of the T-cell inhibitory receptor (CTLA-4) and programmed cell death protein 1 (PD1) to enhance anti-tumor immune responses (17, 18).