PDCD1 and neoplasm: Recently, immune checkpoint inhibitors (ICIs), exemplified by antibodies targeting programmed cell death-1 (PD-1) and programmed cell death-ligand 1 (PD-L1), have demonstrated promising antitumor activity in a variety of tumor types, coupled with low rates of immune-mediated toxicity.10 11 However, studies of anti-PD-1/PD-L1 antibodies in BTCs are limited.