Pancreatic ductal adenocarcinoma(PDAC)is one of the leading causes of cancer-related mortality worldwide,but current clinical methods lack effective screening and treatment options.Despite the widespread use of gemcitabine as a first-line chemotherapeutic agent in the treatment of PDAC over the past decade,its efficacy is limited by the development of drug resistance,which significantly shortens patient survival.This review systematically elucidates the critical role of the tumor microenvironment in the development of gemcitabine resistance of PDAC cells,highlighting the contributions of the extracellular matrix barrier,hypoxia-induced adaptive changes in cancer cells,and the formation of an immunosuppressive microenvironment as key factors in gemcitabine resistance.Additionally,we also introduce novel strategies for reversing chemoresistance,including advanced drug delivery systems,and provide a comprehensive overview of the current opportunities and challenges.