NFKBID (NF-κB inhibitor delta) is an atypical inhibitor of κB protein that modulates NF-κB signaling to regulate inflammatory and immune responses 1. As an inducible nuclear protein, NFKBID localizes to the nucleus upon immune cell activation and functions as a context-dependent modulator of NF-κB transcriptional activity 1. NFKBID plays a critical role in T cell immunity by promoting Th17 cell differentiation and regulating thymic negative selection of autoreactive CD8+ T cells 23. The gene is upregulated in activated B cells through MALT1 protease-mediated cleavage of post-transcriptional repressors, contributing to NF-κB-dependent survival signaling in lymphomas 4. NFKBID also functions in antiviral responses; its downregulation via circRNA-mediated pathways promotes Zika virus replication, indicating it negatively regulates viral infection 5. Clinically, reduced NFKBID expression correlates with poor prognosis in lung adenocarcinoma and bladder cancer, where it associates with decreased immune cell infiltration and worse overall survival 67. In type 1 diabetes, elevated NFKBID paradoxically enhances disease resistance by increasing regulatory T cell frequency despite promoting CD8+ T cell thymic deletion 2.