Fuzion is a set of "universal roleplaying rules" (similar to GURPS, FUDGE, d20, and the Palladium System of rules). It is a combination of R. Talsorian Games' Interlock system (Cyberpunk 2020 and Mekton Z) and Hero Games' Hero System (Champions).
There have been other games which have later been released to use these rules, including Sengoku, Shards of the Stone, Bubblegum Crisis, Armored Trooper VOTOMS, DragonBall Z, Usagi Yojimbo, Campions: New Millenium, and many others. (I kept trying to find the name of the Cyberpunk 2020 game which used Fuzion, but I just cannot find it today. /msg me if you know.)
You can find more information about this system at the website http://www.thefuze.com/ (as of today). You can also download the rules themselves. The games I mentioned above are background settings and some rules "plug ins", to make it easier to play within that setting. The core rules remain the same. This is true for most Universal Roleplaying games, but Fuzion does have the benefit of being a free download!
Do not allow me to dissuade you from trying this game, but I have talked to many of my friends who were both Cyberpunk and/or Champions fans. Not many of them like the game for some odd reason. I haven't played, but I suspect that more than anything they are just being resistant to change. I have a preference for GURPS, so I have never personally evaluated the system.