Avengers: Age of Ultron saw Earth's Mightiest Heroes go to war with a rogue A.I. created by Tony Stark and Bruce Banner. While there were some key differences in how his story played out on the page, Ultron would eventually create The Vision and destroy Sokovia, leading to the events of Captain America: Civil War.
While The Vision is thought to have destroyed the final remnants of Ultron, we never saw him die, and it's long been theorised that he found a way to survive (potentially inside his "son").
Now, The Cosmic Circus is reporting that, "According to one of our sources, the Ultron A.I. was not destroyed in the wake of Avengers: Age of Ultron, and remnants of the Ultron A.I. are still active but 'dormant.'"
What does this mean for the MCU moving forward? They don't know, but we can probably hazard a guess when it comes to when and where Ultron might return. Armor Wars is one strong possibility considering the fact the villain has ties to Iron Man, while Vision Quest seems highly probable as it will deal with White Vision's place in the MCU as he looks to find himself.
That would almost certainly involve exploring his past as the original vessel for Ultron, though the Wonder Man Disney+ series also seems likely given Simon Williams' own ties to the villain.
Marvel Studios has never truly forgotten about Ultron, using him as a big bad in What If...? and in theme park rides such as "Avengers: Quantum Encounter." James Spader played the character in Avengers: Age of Ultron, though Ross Marquand has since lent his voice to the android.
We most recently saw Ultron in Doctor Strange in the Multiverse of Madness when some of his drones apprehended Stephen Strange on behalf of The Illuminati.
Where would you like to see Ultron make his MCU return?