– Roman Reigns sent out a tweet stating that he unfinished business on RAW and would be there Monday to take care of it. While Reigns did not follow up with many details, WWE denied his request. Below are Reigns’ original tweet, WWE’s comment and Reign’s reaction that he will be kicking-off RAW.
— Roman Reigns (@WWERomanReigns) May 4, 2019 
WWE officials have learned of Roman Reigns’ desire to appear on Monday Night Raw, but as of now, and due to his obligations as a Smackdown Live Superstar, he will not be appearing on Monday Night Raw.
— Roman Reigns (@WWERomanReigns) May 5, 2019 
The comments from Reigns are interesting and some have speculated that WWE might run an invasion type angle on RAW. WWE ratings have been on the decline and they are looking for anything to pull them up; especially with SmackDown moving to Fox  in the fall.
During the Superstar Shake-Up , Reigns was drafted to SmackDown. At the time, he had no major feud on RAW after defeating Drew McIntyre at WrestleMania 35 . He has already started a feud on SmackDown with Elias and they will meet at Money in the Bank, which takes place two weeks from today.
– Speaking of low ratings, the Wrestling Observer Newsletter  said to not be surprised if some big names appear over the next several weeks. They mentioned the likes of Brock Lesnar, Bill Goldberg and Undertaker appearing.
With all three confirmed for the June 7 Saudi Arabia show , they could easily be worked into the script as WWE builds towards the unnamed show. Undertaker vs. Elias has been heavily rumored and there is also speculation Lesnar and Goldberg could meet for the forth time. As of now, no matches have been made official for the overseas event.