Differences observed in PK and target desaturation in the circulation are probably due to slightly different levels of target expression on T cells in these two models, as shown for CD8+ T cells within the tumor microenvironment (Extended Data Fig. 4a), and due to upregulation of GITR-L-mediated PD-1 expression (Extended Data Fig. 4b). This evidence concerns the gene PDCD1 and neoplasm.