Here is what has worked for me in the past, try these baby steps:
(1) Do things around the cage (not jumping jacks, just being present is enough). For example, I moved the cage near a desk where I do work frequently. The goal here is for the chameleon to learn your presence does not equate to harassment or threats. Eventually, he will learn that you are something to be watched, but not necessarily a stress-producing threat.
(2) Leave the cage door open (while you are nearby). It's perfectly fine if he doesn't take the opportunity to explore. The real aim here is to keep him from equating the cage opening (and you nearby) to harassment and threats. If he does take the opportunity to explore, watch him to make sure he's safe, but try to be hands off. My theory is that chameleons don't like you, they like things they associate with you. Exploring is one of those things.
(3) Put your hand in the cage for a few minutes, but ALWAYS have your hand holding food. Repeating this should get your chameleon to equate your hand with food. It's fine if he doesn't eat, mine wasn't crazy about cup feeding, but it didn't take long for him to not be afraid of a hand that consistently presented him with food.
(4) Once he is comfortable with (1)-(3), make him think you are a tree, once he climbs on you, take him straight outside. If all of this is done correctly, you will be positively associated with food, freedom, and the outdoors.
Best of luck!