TNFSF8 (TNF superfamily member 8), also known as CD30 ligand, is a cytokine that binds to TNFRSF8/CD30 and regulates T cell function 1. It promotes CD8-positive and alpha-beta T cell differentiation and regulates T cell proliferation through CD30-mediated signaling 23. TNFSF8 expression is notable in memory effector CD4 T cells and tissue-resident memory populations in inflammatory conditions 23. Functionally, CD153/CD30 signaling (TNFSF8/CD30 axis) drives tertiary lymphoid tissue expansion in aged kidneys and promotes interactions between senescence-associated T cells and age-associated B cells, contributing to chr9 kidney injury 1. Disease associations include spondylarthritis susceptibility, with a rare intronic SNP (rs3181357) showing significant association 4, and IgA nephropathy, identified as a genome-wide significant risk locus 5. In asthma and atopic dermatitis, blocking CD30L/TNFSF8 combined with other costimulatory molecules (ICOSL, OX40L) effectively suppresses memory T cell accumulation and reduces inflammation 23. Clinically, hypomethylated TNFSF8 promoters predict anti-PD-1 immunotherapy response better than PD-L1 expression in non-small cell lung cancer 6. These findings suggest TNFSF8 as a potential biomarker and therapeutic target across multiple inflammatory and neoplastic diseases.