WrestleMania 40 is having constant developments that have already suggested that WWE Legends Stone Cold Steve Austin, The Undertaker, and John Cena will be present at the premium live event in significant roles.
Previous reports hinted at "Stone Cold" Steve Austin coming back in some capacity during WrestleMania 40 weekend while John Cena also admitted that he is waiting for an invite to the Show of Shows which is incomplete without his presence.

In an update to the situation, Dave Meltzer mentioned on the Wrestling Observer Newsletter that Austin is not being targeted for any main event slots. Rather, there's been a mystery slot booked on the card of WrestleMania 40 that should be utilized.
"Time will tell, but we were told not to read into that regarding the main events. There is said to be a mystery slot, but whether that mystery is Cena or somebody else is not known."
Ringside News further reached out to a senior member of the WWE Creative Team regarding Meltzer's report about WrestleMania XL containing a mystery slot and denied it. Also, Steve Austin and John Cena were confirmed to be excluded from any in-ring capacity.
WrestleVotes first hinted at the legends' involvement at WrestleMania XL by pointing out the appearance of Cena and Austin's faces on WWE production trucks during the closing moments of Raw where The Rock was assaulting Cody Rhodes.
That segment raised speculations about their potential contributions but the details remain scarce in this capacity. Reports indicated that an offer was extended to Austin but the nature of his involvement remains uncertain if he has accepted the offer.
Apart from Cena and Austin, PWInsider already confirmed multiple names for WrestleMania 40 presence. This list includes names like former WWE Women's champion Michelle McCool and WWE Hall of Famers, Jimmy Hart, Kane, JBL, and Ron Simmons.
WWE WrestleMania 40 premium live event takes place at the Lincoln Financial Field in Philadelphia, Pennsylvania on Saturday, April 6, and Sunday, April 7. The confirmed match card for the grand show goes as follows: