Complex sentence: On December 17,2015, responsibility for overseeing App Store was given to Phil Schiller, Apple's senior vice president of Worldwide Marketing, taking over for Eddy Cue, Apple's senior vice president of Internet Software and Services.
Split into simpler sentences: On December 17,2015, responsibility for overseeing App Store was given to Phil Schiller, Apple's senior vice president of Worldwide Marketing. Previously App Store was led by Eddy Cue, Apple's senior vice president of Internet Software and Services.