There was a rumor from the Eurogamer Expo that Dead Rising 3 was coming to Xbox 360. This report is false.
Major Nelson announced the following statement on twitter:
Reports from #eurogamer that Dead Rising 3 will launch on Xbox 360 are false. It’s an Xbox One exclusive – no plans for 360
The fact that there are “no plans” for Xbox 360 means a ported version won’t be likely in the near future either. Dead Rising 3 will only be available for the Xbox One console from November 22nd.