For the irrelevant RBD–tetramer control group, ex vivo flow cytometry showed negligible staining of CD8+ T cells in tumours (Fig. 4f and Supplementary Figs. 18–21), consistent with the results of in vivo NIR-IIb imaging (Fig. 5d and Supplementary Fig. 17). The gene discussed is CD8A; the disease is neoplasm.