The clinical efficacy of PD-1 blockade in patients with metastatic cancer appears to depend on activation of T-cell populations with T-cell receptors (TCRs), which specifically recognise mutated host molecules, ie, neoepitopes.12 These mutant proteins harbouring point mutations, termed neoepitopes, represent a clinically significant step towards refining T-cell-based immunotherapies and cancer vaccines. Here, PDCD1 is linked to cancer.