The DC and Marvel universes are each defined by a trio of heroes that unite the overarching realities in their own way. For DC, Superman embodies the concept of genuine heroism, Batman what one man can do with enough intelligence, resources and drive, and Wonder Woman brings the mythological and supernatural to bear. Marvel's trinity of Captain America, Thor and Iron Man works in a fairly similar way, though in recent years, they all stepped down from their mantles. And as a result a new, much younger and far more diverse trio effectively took their place.
Specifically, the new trio consists of Miles Morales' Spider-Man, Kamala Khan's Ms. Marvel, and the current Nova, Sam Alexander. All three of them have proven to be an effective trio and cohesive team, and the shared experience they have of being forced into inheriting a big legacy has served as a much more effective link between them than Cap, Thor and Iron Man have.
Like all teenagers, their first meeting ( which came in the early issues of All-New, All Different-Avengers) saw them not getting along well, with Kamala going overboard in chastising Sam for being too destructive in a short Jersey brawl. But a fun dynamic between the three of them developed as they navigated their way through being Avengers alongside Vision, Tony Stark, Sam Wilson during his Captain America tenure, and Jane Foster's Thor. The decision to add the three of them in as the first Avengers team post-Secret Wars and Miles' transfer to the prime Marvel Universe shows how far they came in the preceding years, and in the lead up to the multiversal mashup.
Though the three of them aren't exactly a grouping that you'd call conventional, it's been shown time and again that they's more than capable of picking up the slack left by their predecessors, and in some ways even succeed where more experienced fellow heroes have failed. In particular, they surpass the original Avengers trinity in that they actually feel like a trinity.
Since the original Civil War in 2007, it could be argued the original trio was more like a duo: both Civil War and the Secret Wars prelude Time Runs Out were primarily about Steve and Tony's clashing ideals while Thor was simply a game piece for both to move around when he allied with either one. It was Steve and Tony who vetted various candidates for the Avengers Machine during Hickman's run rather than the three of them. Even in the midst of Odinson's recent troubles, where he could no longer pick up his hammer Mjolnir, he never really interacted with either of them, instead choosing to wallow in self isolation.