To open a trunk when there is no key and the cable release is broken, it is necessary to remove the back part of the rear seat. In some vehicles there is a small part of the bench seat back that will pull down to access the trunk.
Even if the trunk release is broken, the external key lock should be able to open the trunk.
dealers can do it - they have a way to get in from the engine compartment but won't share how it is done :(
how to get a 2001 isuzu trooper hood open if release cable is broken
With the power roof button. If its broken.... I heard there's a cable you can turn behind the trunk.. accessed from trunk.
Release cable in trunk up against firewall in rear
Look in the trunk- there ought to be an emergency release- you might have to pull the trunk's liner back a bit to access this cable with a tab attached to it.
Sawsall
if you can pull out the cable cut off some of the cable were you can see the wire inside and pull the cable to open
Take it to a body shop as they have to open then on wrecks.
grab the broken end of the cable with vice grips and pull it
HOW DO I OPEN HOOD ON CAR WHEN CABLE IS BROKEN