Although many studies were conducted to find a perfect biomarker that is helpful in the evaluation of IBD disease activity, the prognostic efficiency is not satisfactory, and an ideal prediction model has not yet been established.[37,38] Based on the background, we turned to an immunological balance, the CD8+CD28+/CD8+CD28– ratio, to validate a more powerful prediction model. Here, CD28 is linked to inflammatory bowel disease.