Even though there was very little chance of the match happening, WWE creative was recently told officially that John Cena vs. The Rock would not be happening at Wrestlemania 26.
Apparently Vince McMahon really wants to put this match together, putting the two moviestar-wrestlers against each other, even having Cena mention it in interviews.
The Rock is still likely to make an appearance for WWE as a Raw Guest Host or in another capacity, but its unlikely that it will be a match.
credit: Wrestling Observer Newsletter