Lecture : Despite advances in medical technology, Pancreatic ductal adenocarcinoma (PDAC) is still a cancer disease with a high mortality rate. In particular, compared with other cancer diseases, the PDAC has a meager survival rate. PDAC has unique pathobiological features called tumor microenvironment (TME) that defeat existing therapies. The desmoplastic stroma surrounding the tissue is known to induce the growth and metastasis of cancer cells and to inhibit the intra-tumoral penetration of therapeutics. Also, the immunosuppressive TME of pancreatic cancer promotes cancer growth and metastasis by inhibiting the activity of immune cells in tumor tissues. Understanding of the TME of PDAC, as found in recent studies, has allowed the TME to be targeted to improve the treatment efficacy significantly. This lecture will cover the latest trends in pancreatic cancer therapies using TME targeting, with an understanding of the TME characteristics of PDAC.