6‐Mercaptopurine potently inhibits recruitment of SHP2 by phosphorylated PD‐1 to inhibit PD‐1 signalling and enhance T cell function. - Liu, Lu; Lei, Yuxi; Zheng, Zongyao; Zhou, Xingang; Chen, Shuzhen; Zeng, Guandi; Yu, Lei; Wang, Peng; Chen, Liang (Immunology, 2023)