Three possible candidates:
The lock cylinder is broken
The linkage from the lock cylinder to the latch has popped off
The latch is broken.
If you can turn the key in the lock cylinder; but, nothing happens then the lock cylinder is probably OK. Its likely that one of the retainers holding the links (there are two - its a bell crank arrangement) to the latch has popped off allowing one of the links to drop out of place. If you can't turn the key freely in the lock cylinder, then the cylinder may be jammed and replacement is in order (this also requires re keying). Its the pins in the cylinder that usually wear and jam so you might be able to get away with just having a locksmith replace the pins. If the cylinder turns freely and the links are in place then it could be the latch - ouch because there are no user serviceable parts and its rather expensive. Given your symptoms, I would put money on the missing link.
Regardless of the cause, you are going to be doing the deep dive into the door cavity to check things out. Get a copy of the service manual or at least the section describing removal of the interior panel because there are a few hidden screws and items that are not obvious. If you search Prime, I do recall a thread with pictures covering removal of the interior door panel. When you reassemble the door panel, go easy on tightening the screws on the plastic tabs around the outside edge of the door panel. Get too enthusiastic with tightening and it is easy to snap the tabs off.