Data derived from a study of 19 Asian patients with MSI-H gastric cancers treated with second- or third-line pembrolizumab in the context of a phase II study described that tumours with features such as higher TMB, T-cell receptor (TCR) pathway activation and a more diverse TCR repertoire, and the presence of stem-like exhausted CD8+ T-cells are associated with benefit from pembrolizumab. Here, CD8A is linked to neoplasm.