In tumour CD8+ T cells, treatment with anti-PD-L1 sustained expression of the gene program associated with exhaustion, characterized by the transcriptional regulators Tox, Nr4a2 and Id2 as well as the co-inhibitory receptors Pdcd1, Tigit, Lag3 and Havcr2. By contrast, treatment with anti-TIGIT antibodies drove a shift in tumour CD8+ T cells away from that program and towards one associated with memory state, with elevated expression of Tcf7, Klf2, Ccr7, Lef1, Il7r and Sell (Fig. 4c). The gene discussed is PDCD1; the disease is neoplasm.