The editorial in Frontiers in Immunology discusses Inborn Errors of Immunity (IEI) and their impact on immune homeostasis and tolerance, with a focus on T regulatory cells. IEI are caused by mutations in genes regulating immune processes, leading to susceptibility to infections and immune-related complications. The article highlights the classification of IEI into 9 groups and introduces the concept of Primary Immune Regulatory Disorders (PIRDs) and Tregopathies. It also explores the role of Tregs in various immune disorders and potential therapeutic approaches for IEI.