It looks like John Cena will be working the July 23rd WWE Battleground event.
John Cena has just been added to the SmackDown brand Battleground event, which is the final pay-per-view event before SummerSlam. It’s not known yet exactly what his role will be on the show.
Cena is scheduled to make his WWE return on the July 4th episode of SmackDown Live. He has been out of action since WrestleMania 33 in early April. As of this writing, he is rumored to work a program against Jinder Mahal at the SummerSlam event. It is very possible that he faces Mahal before hand.