PDCD1 and cancer: Immune checkpoint inhibitors, such as programmed cell death protein 1 (PD-1) and programmed cell death ligand 1 (PD-L1) inhibitors, are being investigated in clinical trials, harnessing the immune system to combat cancer cells (Fig. 1).20 Guided by genomics and biomarker research, personalised medicine allows for customised treatment plans based on an individual's unique cancer profile, optimising therapeutic outcomes.21