TMAO has been shown to improve anti-PD1 and/or anti-Tim3 immune checkpoint blockade in pancreatic ductal adenocarcinoma by potentiating IFN-g response [21] and activating CD8 T cell antitumor response, as well as by directly inducing the pyroptosis of tumour cells by increasing endoplasmic reticulum stress in triple-negative breast cancer [22]. Here, CD8A is linked to neoplasm.