PDCD1 and cancer: In the past few years, immune checkpoint inhibitors (ICIs), particularly programmed cell death protein 1 (PD-1) or programmed cell death protein ligand 1 (PD-L1), have brought advancements to adult cancer treatment, resulting in remarkable breakthroughs.1–3 It is worth noting that blockade of PD-1/PD-L1 pathway have demonstrated significant improvements in the outcomes of adult cancer patients.