Ultrasound can alter the state of lipid membranes through mechanical, thermal, and sonochemical effects. Moving beyond the view of membranes as passive carriers, this review examines membranes as both targets of ultrasound-induced stimuli and tunable functional interfaces in cancer nanomedicine. We compare the acoustic response characteristics of natural cell membranes, artificial lipid membranes, and hybrid membranes from the perspective of membrane engineering, discussing how membrane deformation, phase transition, and oxidation contribute to hypoxia alleviation, localized drug release, combination therapy, and immune modulation, while the evidence directly linking membrane changes to therapeutic outcomes remains limited. We propose that a key to clinical translation is to establish a quantifiable and reproducible relationship between membrane composition, in situ acoustic exposure, membrane response, and therapeutic output. Redefining membranes as tunable acoustic-responsive interfaces could provide a more controllable design framework for ultrasound-enhanced cancer nanotherapy.