Today, when you think of the Marvel Cinematic Universe, you likely picture the massive superhero crossovers, the billions of dollars in box office money and the immense impact the series has had on Hollywood as a whole. When considering the sheer scope of the MCU, it's funny to think that it all began with 2008's "Iron Man" and a rebounding Robert Downey Jr., who was just beginning to make his comeback as a star.

Fast forward to today, and Downey is the face of the MCU, with Iron Man inarguably the most popular character. Yet Downey, whose contract with Marvel is coming to a close after the two-part "Avengers: Infinity War" series, has made it known that he will only continue as Tony Stark if the studio can offer him interesting opportunities. That's why we're getting the highly anticipated "Captain America: Civil War" instead of "Iron Man 4."

Yet a new unconfirmed report suggests that Marvel is starting to lay the groundwork for a fourth "Iron Man" film after all, albeit one that won't arrive until at least 2020. Again, this isn't coming directly from Marvel, so don't consider it gospel just yet.

Audiences last saw Tony Stark in a solo adventure in 2013's "Iron Man 3," which put up more than $1 billion at the box office. We'll next see him in "Civil War" and then "Infinity War," so it's not as if the character is disappearing from the MCU. But given Downey's contract situation and age (he'll be 55 in 2020), it's possible that Marvel could recast the role. As we've seen with Hugh Jackman's Wovlerine or Christian Bale's Batman, there's only so long an actor can play one role.

Marvel could also opt to replace Downey instead of re-casting him. Don Cheadle's Iron Patriot/War Machine officially joined the Avengers squad by the conclusion of "Age of Ultron." Though he doesn't carry the same name recognition or box office appeal as Downey, his character has been fully integrated into the MCU (though Cheadle is one year older than RDJ).

At this point, this is all just random speculation. There's no doubt that Marvel will want to continue the "Iron Man" franchise one way or the other as it is one of its most bankable properties. Whether or not Downey is involved with those plans remains to be seen.

At least we have "Captain America: Civil War" arriving on May 6 to look forward to.