Using RNA-sequencing data from The Cancer Genome Atlas, Brown et al. used tools to predict whether missense mutations found in tumours from 515 patients were likely to result in neoantigens that could be presented by major histocompatibility complex (MHC) class I. Tumours producing neoantigens that were predicted to be bound by MHC class I correlated with CD8A expression (a surrogate for the presence of CD8+ tumour-infiltrating lymphocytes) and patient survival. The potentially immunogenic tumours had increased expression of RNAs encoding the immune checkpoint proteins PDCD1 and CTLA4, indicating that these tumours might benefit from immunotherapy that suppresses immune checkpoint signalling.