It could be the starter of the truck, the battery cables, or a blown fuse. Get an extensive inspection done on the starter or battery system to find out for sure.
My alarm on my car went off when someone installed a new battery and the guy took the battery out. The alarm system was still activated when he reattached it, so the car would not start (because the alarm system prevented it from starting as a safety precaution). That might be the case with your truck as well.
if the starters still working and it doesn't start and it has something to do with ignition coils carburetor gas but if it doesn't do anything when you turn the key it's either a fuse or solenoid good luck