Lesnar is currently scheduled to announce his cash-in decision on Monday's RAW and then may return for the final episode before Super ShowDown, which would be the June 3 episode, according to Dave Meltzer on Wrestling Observer Radio. Meltzer noted that Lesnar will then work Super ShowDown, but after that we likely won't see him until around SummerSlam time in August, to set up his match for that pay-per-view.
The plan has been for Lesnar to face Rollins at Saudi Arabia, as far back as around WrestleMania 35 time. It is possible that WWE announces Lesnar vs. Rollins as a regular match, and have him keep the briefcase, but that seems unlikely.
There had also been some speculation on Lesnar vs. WWE Champion Kofi Kingston, but it's now confirmed that Kofi will defend against Dolph Ziggler at Super ShowDown. It's interesting that WWE went ahead and announced Ziggler vs. Lesnar when they are teasing Lesnar's announcement on Rollins or Kingston for Monday's RAW.
As noted, Ziggler's return was a late decision because Kevin Owens turned down the return to Saudi Arabia. Owens vs. Kingston was originally scheduled for Super ShowDown.