John Cena is being advertised for the Battleground PPV on July 23, which is a SmackDown PPV.
On the Wells Fargo Center website, it says:
Wells Fargo Center is excited to announce the addition of “Free Agent” John Cena to WWE Battleground on Sunday, July 23. Now in its fifth year, WWE Battleground has turned into one of WWE’s most exciting events. What will WWE have in store when this year’s SmackDown LIVE-exclusive pay-per-view comes to the City of Brotherly Love?
The rumor has been that “free agent” John Cena may be able to appear on either brand as he wishes, and the above indicates that he’ll at least still wrestle for SmackDown (for now).