These antibodies mitigate T cell inhibition by disrupting the interaction between PD-1 on activated T cells and PD-L1, which is expressed on tumour and various immunosuppressive cells within the tumour microenvironment (TME), such as tumour-associated macrophages (TAMs), regulatory T cells, and myeloid-derived suppressor cells (MDSCs)2–4. The gene discussed is PDCD1; the disease is neoplasm.