As with all rumors, we strongly suggest taking this with a grain of salt. With that said, the tease of Atlantis being part of the MCU during Avengers: Endgame could pay off sooner than later according to a rumor from The Illuminerdi. According to the report, Namor The Submariner is set to hit dry land in Black Panther 2, when we will meet him as The Savage Submariner as he leads an attack on either all of humanity or possibly just the citizens of Wakanda.
If the report is accurate, the role of Namor has already been cast as Narcos: Mexico actor, Tenoch Huerta. The report goes on to assert that casting is now under way for both Namora and Cadmael.
The idea of bringing Namor into the MCU after DC has already introduced Jason Mamoa as Aquaman has a small amount of risk, but between Namor’s storied history as both a hero and villain, as well as his love triangle between him, Susan Storm, and Reed Richards make him nearly impossible to pass up, especially as we get closer to the eventual unveiling of the Fantastic Four in the MCU.