You can build on this in may different ways.
1) Movement - Looks to me like it's time to move your hand a little. Start with just a very short distance (have his step up from the cage, move your hand an inch or so away, then move it right back). Initially, let him eat the treat during the entire motion, so he has incentive to stay put while he's in motion. Have him step up from one corner and step down onto another.
If being moved away from the cage frightens him, try moving him laterally by sliding your hand along the cage edge. This will 1 - support your hand to help it stay extra steady, and 2 - provide him the opportunity to jump off at any time.
2) Location - In the mind of your bird, stepping up from two different locations are two totally different behaviors. Depending on your layout, I'd suggest repeating the behavior from all different angles, and also try changing the angle of your fingers (parallel vs. perpendicular to the cage).
3) Distance - You already have him jumping to your hand. If you slowly increase the distance, you'll soon have him flying to your hand. From there, you can practice having him fly different directions, moving upward or downward, and for advanced studies - around corners.
4) Step down/reverse - Once you can move him a bit, try having him step down onto a perch/chair back/whatever you have handy, then stepping up again from this new location. Additionally, you can work on having him fly not only to you, but back to the cage/other designated location on command (station).
The end goal should be a bird you can call, send away, pick up, or set down, wherever and whenever you please, and he should trust you to provide stable surfaces and make it worth his while to cooperate.
5) Have you tried working on other tricks? I find simple things like "wave" and "turn around," are pretty easy for them to learn, and use them as sort of a palate cleanser between more challenging training.
All in all, I see a great start. Your bird is engaged, interested, and doesn't seem remotely fearful. Good job!