A new rumor details that Marvel Studios is in the early stages of development for a Thunderbolts live-action property.
Mostly, this means they are writing a screenplay for it. It’s the phase before pre-production, and can often get stuck in what folks in the industry have called “development hell.”
A number of films have fallen into this trap over the years. Akira being the most recent example, being a project in development since 2002, and recently being delayed even after being produced by Andrew Lazar, Leonardo DiCaprio and directed by Taika Waititi. Another example? Gambit.
The rumor comes from Jeremy Conrad at MCU Cosmic: 
“A Thunderbolts project is now in very early development at Marvel. Most people want to see them on the big screen, but in the Disney+ era and the emphasis Marvel Studios is placing on the service and its importance to the MCU; the possibility of the team starting there in a series can’t be ruled out.”
There are no names, sources, or pictures attached to the project. So everything at this point is just a rumor. But I think I can say that there isn’t a lot of online activity clamoring for the Thunderbolts as a live-action film or television series. If there are circles of the internet interested in seeing this property go forward in the MCU, I’m not seeing them.
However, after seeing that mock-up image of the more notable characters standing side-by-side, I’d probably want to see those characters take jabs at each other in live-action as well.
In the Marvel NOW! publication (2013), General Thaddeus “Thunderbolt” Ross puts together a rag-tag team to save the world. Kinda. The tone of the book is very much like DC Comics Suicide Squad, but with a mix of villains and loosely defined heroes. Ross leads them as the Red Hulk. The team consisted of the Punisher, Deadpool, Elektra, Agent Venom, Ghost Rider, Mercy, and Red Leader.
We already have Deadpool slated for a third film as Disney tries to figure out how to incorporate the R-Rated hero with their properties. And Ryan Reynolds has been day-1 with the Disney franchise, making fun of it in his Deadpool persona with every chance he gets.
The Punisher is still in a cool down period from his solo series. Whether Jon Bernthal will return to reprise the role from his Netflix characterization is anyone’s guess at this point.
Elektra is a character from the Daredevil solo series also in a cool down period. There hasn’t been a peep online about Elodie Yung reprising the role of the female ninja-assassin.
Ghost Rider was supposed to be getting his own series on Hulu spinning out of Agents of S.H.I.E.L.D., but that series was subsequently canceled.
And as far as Hulk villains go, we have only had hints of The Leader making an appearance, although rumors indicate he could show up in the announced She-Hulk Disney+ series.
As for Mercy, maybe we’ll get a glimpse of her in Eternals. She is an immortal with a variety of bizarre powers. Her mission “of mercy” is to help those who wish to die yet are unable to muster the strength within themselves to commit suicide.
The Real Thunderbolts
The news coming from MCU Cosmic seems to be preemptive for what’s to come in the MCU on the ground level. More particularly, in anticipation for the upcoming series The Falcon and The Winter Soldier and the Black Widow film.
The series and film are espionage flicks, littered with gritty action and thrills. Akin to films like Jason Bourne or the James Bond franchise. And so the series probably won’t get into some of the more cosmic-powered, reality warping stuff like Wandavision or Doctor Strange.
The importance of Baron Zemo in The Falcon and the Winter Soldier also is interesting to note. Mostly because the Thunderbolts originated with Baron Zemo and the Masters of Evil. And that team started as a group of mostly villains performing heroic acts. All in an attempt to gain public trust and access to resources and positions of authority.
Zemo in the films has been a master manipulator, able to turn the superhero team of Avengers against each other. This brought about a rift in the ranks that left the members, and Earth, open for attack in the later film Avengers: Infinity War. It will be interesting to see his role in the upcoming Falcon and The Winter Soldier series. As well as how it could set up the future for the MCU films.