#3 Brock Lesnar switches brands

Brock Lesnar last competed at WWE SummerSlam in a losing effort to Roman Reigns. At Hell In A Cell, Lesnar would decimate Reigns thus causing a disqualification between Braun Strowman and Roman Reigns. Ever since then Lesnar has been absent from television. Could there be a specific reason?
Lesnar has a storied history with the SmackDown Live brand. He spent his first tenure in WWE primarily on the blue brand. During his brand tenure, he was WWE Champion and participated in stellar matches. Moreover, Lesnar helped develop the brand.
With the 1000th episode around the corner, it would be awesome to see a returning Lesnar. It could be a one-off appearance. Moreover, it could be in a match. Notwithstanding, perhaps the best direction would be Lesnar switching brands. He has dominated Raw. Therefore, he could dominate SmackDown once more. However, it must be noted, he may still have unfinished plans on Raw.
His presence on SmackDown Live affords multiple possibilities. Lesnar could feud with any of the following; AJ Styles, Shinsuke Nakamura, or Daniel Bryan. Ultimately Lesnar has proven his worth. Moreover, he has wrestled in Japan, see video below. It is now the time to capitalize on his success in wrestling and MMA.
What could we expect?