Never saw this due to not being dubbed in English and airing in America, but seeing some subbed episodes, I am treating this as some sort of alternate universe. Basically, Evolution tries to act like a sequel series, but sadly, it fails.
Basically, XANA's revived and the Lyoko Warrriors have to stop him again. However, this "sequel" decides to ditch the cartoon parts for live action actors while ignoring certain elements the original series established (like Aelita is not the only one who can deactivate towers, plus some characters have been changed for the worst, with Aelita getting it worst, as she sounds more serious).
By ditching the cartoons for live action, it basically results in the characters being played by actors who don't fit the role (seriously, Odd does not look like Odd). This also put a limit on XANA's attacks. In the original, XANA could mess up a lot of things that could actually make him a threat, but here, all he does is fry phones and send specters. Also, we get a second antagonist in one Professor Lowell Tyrone, a character whose invention is the McGuffin for X.A.N.A.'s survival, and a new character named Laura who is sadly an unnecessary character, as she is basically a female Jeremy.
It's no wonder this series only lasted one season. With such disrespect to the source material, as the original writers of Code Lyoko would disown this after finding out about how the show was ignoring the source material. This is best viewed as an alternate universe, and not a very good one at best.