Brock Lesnar's future with WWE is up in the air right now.
According to Wrestling Observer, Brock Lesnar has one match left on his WWE contract which is consistent with the per appearance relationship between WWE and the Universal Champion that has been reported. He re-signed in April before the Greatest Royal Rumble event which was his last appearance on WWE programming.
At Greatest Royal Rumble, Roman Reigns failed for the third time to beat Brock Lesnar in a Championship match and since then there has not been a challenger selected for Lesnar.
Lesnar did not appear at Money in the Bank and it seems he won't defending his Championship at Extreme Rules because Kurt Angle recently announced a number one contender multi-person match for that pay-per-view. Bobby Lashley and Roman Reigns have been announced for that match. Extreme Rules will be followed by the SummerSlam pay-per-view.
Brock Lesnar could also be looking at a matchup with Braun Strowman as he won the Money in the Bank ladder match which entitles him to a WWE Universal Championship match.