Kang the Conqueror, played by Jonathan Majors. It is believed that he has only signed a one-movie deal, but that Kang, or different iterations of him, will be the next major villain ala Thanos. It's also believed that Marvel is assembling a team of villains: Loki, Zemo, US Agent (Wyatt Rusell), Madame Hydra (JLD), and more for a Thunderbolts movie or show.