PDCD1 and cancer: The first clinical trials were recently performed with autologous transfer of T cells modified to express a synthetic TCR transgene that recognizes the cancer-testis antigen NY-ESO-1, while the genes for the α and β chains of the TCR (TRAC and TRBC) were deleted using CRIPS-Cas9 to prevent competition with the transgenic TCR, as well as the gene for PD-1 to prevent T cells deactivation [347].