PDCD1 and neoplasm: The first ever approved tumour-agnostic drug was the monoclonal anti-programmed cell death protein-1 antibody pembrolizumab.2 Although developed and initially approved in 2014 for specific indications including advanced melanoma, in 2017 the FDA broadened the approval of this immune checkpoint inhibitor to include adult and paediatric patients with microsatellite instability-high and mismatch repair-deficient tumours.