Work by the Sharpe laboratory demonstrated that PD‐1 and its ligand PD‐L1 are important for pTreg cell development and function.134 Subsequently, PD‐1 was demonstrated to contribute to tTreg cell stability in Foxp3low conditions.135 Moreover, PD‐L1 expression on antigen‐presenting cells can expand Treg cells in patients after allogeneic bone marrow transplants.136 However, in the context of cancer, PD‐1 expression by Treg cells has been associated with their dysfunction.137. The gene discussed is CD274; the disease is cancer.