Sade-Feldman et al. found that the presence of a single transcription factor (TCF7) alone, visualized on CD8+ T cells of fixed tumor samples can predict clinical response to ICB in melanoma patients, suggesting that the state of T cells found in a patient’s tumor, in addition to the number of T cells and their spatial distribution, are also critical for induction of effective tumor immunity [117]. The gene discussed is CD8A; the disease is neoplasm.