Keywords: Immune check point inhibitor; Immune-rerated adverse events (irAE); Gastritis; Enteritis; Colitis EN Immune check point inhibitor Immune-rerated adverse events (irAE) Gastritis Enteritis Colitis 2129 2134 6 05/31/21 20210601 NES 210601 Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10620-020-06441-w) contains supplementary material, which is available to authorized users. The side effects of ICI are generally referred to as immune-related adverse events (irAE), and irAE gastroenterocolitis is considered one of the important side effects. In particular, pathological features of irAE colitis were similar to those of IBD, but our cases demonstrated epithelial apoptosis without distortion of glandular structure is a feature often found in irAE colitis. In the case of irAE colitis, it is generally said that the main findings are located in the rectum and sigmoid colon [[5]], and therefore, many doctors recognize that sigmoidscopy is sufficient to make the diagnosis of irAE colitis. [Extracted from the article]