SPHK1 and ovarian cancer: Using both in vivo and in vitro methods, we demonstrated that i) EVs‐SPHK1 (SPHK1‐packaged EVs) induce immune suppression in ovarian cancer and ii) targeting SPHK1 with a specific inhibitor, PF543, in combination with anti‐PD‐1 therapy enhanced immune activation in ovarian cancer patients, thereby improving survival.