While Stan Lee is frequently credited as the sole creator of many iconic Marvel Comics characters, the artists he worked with have long disputed that claim.
Attorney Marc Toberoff represents Larry Lieber (Lee's younger brother) and the estates of Don Heck, Gene Colan, and Don Rico, and recently attempted to terminate Marvel's copyrights of Iron Man, Ant-Man, Captain Marvel, Thor, Black Widow, Hawkeye, and Blade.
In response, Marvel filed lawsuits right back at them, though a settlement has now been reached.
The Disney-owned company's response was that these artists did work-for-hire, thereby meaning Marvel owns these characters in perpetuity (leaving the artists with no right to reclaim them under the Copyright Act). The lawsuits have been dropped with prejudice, bringing an end to the matter once and for all.
According to both a Disney spokesperson and Toberoff, both sides have reached an "amicable resolution." Details of that are unlikely to be revealed, though we'd imagine they've been compensated financially in a way that's made everyone involved happy.
However, no settlement has been reached with the family of Steve Ditko. They're looking to reclaim his share of the Spider-Man and Doctor Strange copyrights, though it's likely Marvel will emerge triumphant there as well.
It was back in 2013 that Marvel won a similar case at a U.S. appeals court regarding Jack Kirby, the co-creator of characters like Captain America and the Fantastic Four. That case was also eventually settled.
Marvel Studios will release a Stan Lee documentary on Disney+ this Friday, though that looks set to be more akin to a celebration of his life rather than any sort of exploration of whether the artists he worked with were credited properly.
The odds of Marvel ever losing the rights to its iconic superheroes are somewhere between slim and none, but these cases are always worth keeping a close eye on.