Wanda Will Become The Scarlet Witch
Doctor Strange in the Multiverse of Madness' trailer teased the introduction of the Illuminati, and the possibility that Scarlet Witch kills the new superhero team.
Wanda Meets Her Destiny Of Destruction
Doctor Strange 2 featured plenty of surprises about the movie's cast, story, and use of the multiverse. One fact it doesn't directly clarify is who the main villain is, though there are lot of prime suspects, including Wanda Maximoff and her destiny to become the Destroyer Of Realms.
Darkhold: Book Of The Damned
As more marketing materials for Doctor Strange 2 are released, more evidence that Scarlet Witch is the villain has been revealed. The black fingertips featured in the first trailer teased the influence of the Darkhold over Wanda and its dark magic corrupting her, just as it did to Agatha Harkness.
Wanda's Jealousy Of Dr. Strange
In the new Doctor Strange trailer, she's seen fighting different characters and covered in blood, while one of her lines of dialogue even mentions the hypocrisy between how her use of magic and Strange's are perceived, hinting a rise of her dark side more and turning into a villain.
Illuminati is a team of the most powerful or the most insightful put together by Tony Stark (confirming the rumor of 'A Tony Stark' in the sequel). The MCU Illuminati is similar to the real world Illuminati only difference is that they put together their power to fight the evil not control it.
Wanda's Not So Friendly Visits
The Illuminati and their members does not appear a lot but their headquarters where we see Ultron bots capturing Dr. Strange has a bit more prominent appearances, There are a few different moments that show Wanda in the Illuminati's base, and each one indicates this isn't a friendly visit.
One scene appears to show Scarlet Witch fighting the Captain Marvel variant inside the headquarters, which leads to an energy explosion when the photon blasts and chaos magic meet. This confirms that Wanda and members of the Illuminati will fight, even if the reason for the battle is unclear.