Exhausted T cells are characterised by the loss of function of cytokine production or cytotoxic activity.10 T cells receive an inhibitory signal after binding of PD-1 and the ligands PD-L1 or PD-L2, expressed on antigen-presenting cells (APCs) and tumour cells, resulting in the suppression of proliferation, cytokine production, and cytotoxic activity. The gene discussed is CD274; the disease is neoplasm.