
Thunderbolts* finally introduced the MCU's New Avengers in a surprising twist, and they are vastly different from the original version of Earth's Mightiest Heroes. The new team of villains-turned-heroes in Thunderbolts* consists of Yelena Belova, Bucky Barnes, Ava Starr as Ghost, Red Guardian, and Bob (aka Sentry).
After the Thunderbolts* final battle saw the titular team of misfits successfully defeating its big bad, The Void (a dark version of Sentry), they shifted their attention to Valentina Allegra de Fontaine (Val) for betraying them and manipulating them into killing each other in the early moments of the movie.
However, Val tricked them into an impromptu press conference, announcing them as the New Avengers.
Here’s How the MCU’s New Avengers Are Different From the Original Team

At the end of Thunderbolts,* Val took credit in the press conference that she was the one who formed the New Avengers, pointing out in her speech that she has been "working secretly to develop a new age of protection" for the citizens of the United States:
“For years, I have been working secretly to develop a new age of protection. Today, the citizens of the United States need that protection, and thanks to my hard work, they got it. Ladies and gentlemen, meet the New Avengers.”
One of the main differences between the MCU's New Avengers and the Earth's Mightiest Heroes from the Infinity Saga is the fact that the public is skeptical about the creation of this new team as shown in the various headlines presented in the Thunderbolts* credits (unlike in the 2012's The Avengers where people worldwide celebrated the original team's formation).
While the Thunderbolts did manage to save New York from The Void, the reason behind the public's adverse reaction to the New Avengers' introduction may be related to the fact that the members are former villains/anti-heroes, meaning that they can't place their trust in them due to their past.
Thunderbolts* lengthy post-credits scene also included John Walker saying that he saw some "nasty memes" about their team on social media, implying that the public still has yet to accept them, even if they have already been recognized as the current Avengers for 14 months.
The current New Avengers lineup consists of three super soldiers (Bucky, Red Guardian, and US Agent), a Black Widow (Yelena), a stealth operative who can turn invisible (Ava Starr/Ghost), and an unstable powerhouse who can't risk using his powers because his inner demon could re-emerge (Bob/Sentry).
The team's lineup is clearly lacking enough firepower to stand its ground against otherworldly threats.
Still, Yelena pointed out that they are the government-sanctioned Avengers, potentially hinting that they are definitely the first choice to respond to any threat, even if they are losing credibility with the public.
The New Avengers in Marvel Comics Explained

In Marvel Comics, the most recognizable iteration of the New Avengers came after the original Avengers disassembled permanently. The team debuted in New Avengers # 1 by Brian Michael Bendis and penciled by David Finch in January 2005.
The initial members include Captain America, Iron Man, Luke Cage, Spider-Man, and Spider-Woman (who is secretly a Skrull) before it expanded to add the likes of Wolverine, Ronin, Echo, Ms. Marvel, Mockingbird, and the unstable Sentry (who is also part of the MCU's New Avengers in Thunderbolts*).
Unlike the Thunderbolts-turned-New Avengers in the MCU, the comics' version of the team is not government-sanctioned. Instead, they did not comply with the Superhuman Registration Act.
Will Sam Wilson's Avengers Join Forces with the New Avengers in Doomsday?

Ahead of Avengers: Doomsday, Thunderbolts* post-credits scene teased a brewing conflict between Bucky Barnes and Sam Wilson over who the real Avengers are.
While the New Avengers are the current government-sanctioned team of heroes in the MCU, Yelena and the others feel they are being kept out of the loop of important matters due to the public's mistrust.
Making matters worse, Sam filed for copyright of the name, "Avengers," so that his team could officially use it.
Although the two teams are fighting over the "Avengers" name, there is a strong chance that this will be put on the back burner as they deal with the arrival of Robert Downey Jr.'s Dr. Doom (one of the most powerful characters in Avengers 5) alongside the incursions that threaten their universe.
Yelena's New Avengers and Sam Wilson's Earth's Mightiest Heroes will likely set aside their differences and form a stronger team to address the looming multiversal threat.