In a recently published landmark study comprising tumor tissue samples from 2681 patients with stage I–III colon cancer, Pagès et al. could demonstrate that the numbers of CD3+ and cytotoxic CD8+ T cells in the tumor directly correlated with time to recurrence in both the training and validation cohorts, independent of MSI, T and N stages and other clinicopathological factors. The gene discussed is CD8A; the disease is neoplasm.