B777-300 flight crew reported on departure they received an aft cargo door indication. Flight crew decided to return to the departure airport and made a successful overweight landing.

Narrative

Shortly after takeoff got a door aft cargo indication. Aircraft was pressurizing normally. Started non normal checklist and item on checklist was to depressurize aircraft; we stopped climb at 8000 ft and completed non normal checklist. Then completed the overweight landing checklist with associated performance calculations. Decision was made to land back at ZZZ with overweight landing as all conditions were met to be able to do so. Then completed the non routine landing checklist and briefed the Dispatcher; Flight Attendants; and Passengers. [Priority was requested] to have fire trucks available as we would be overweight and high energy landing. Landing was made using ILS XXL flaps 25 auto brakes 3 at about 616;000 lbs. and 150;000 lbs of fuel. Landing was soft touchdown and nominal braking bringing aircraft to stop on runway to give Crash Fire Rescue (CFR) a chance to inspect brake and tire conditions. Everything was good and taxied to gate without issue. Log book entry's made for overweight landing and aft cargo door indication.Cause - Cargo door fault.Suggestion - Better Maintenance.