Although the Avengers Initiative was instigated by S.H.I.E.L.D. around the events of the first Iron Man film, the chronology of the MCU before that film released is still somewhat blurry. Captain America fought Hydra in World War II, and Captain Marvel got up to something during the nineties, but surely there must've been something else that spurred Phase 1?
Ant-Man and the Wasp were, of course, active S.H.I.E.L.D. Agents during the Cold War, but they weren't superheroes in the typical sense - at least not to the level Carol Danvers presumably was during the events of her film. Judging by past comments from Marvel Studios that the character is also one of - if not the - most powerful MCU heroes, logic would dictate that her entrance marked a shift in attitudes from S.H.I.E.L.D., and one Nick Fury in particular.
Past canon has indicated that Hawkeye and Black Widow didn't form a part of Fury's strike-force until 1998, and it would be a further decade before Tony Stark would mark his entrance as Iron Man. That said, don't be surprised to see the burgeoning moments of the Avengers Initiative pop-up in Captain Marvel, as well as its possible cooption by the shadier elements within S.H.I.E.L.D.'s ranks.
WhatCulture's very own resident movie guy, Ewan has been working in the content creation biz for over 10 years now, having started as a freelance contributor to WhatCulture Gaming all the way back in 2015. After graduating with a First-Class Honours in History from Northumbria University in 2017 (where he won a prize for a totally killer dissertation on the Watergate years), Ewan took on the role of Comics Editor at WhatCulture and quickly developed WhatCulture Comics into one of the biggest superhero-focused channels on YouTube. He followed this with a brief hiatus at Screen Rant in 2021, where he worked across the Gaming and Film sections as a writer and editor, before returning to WhatCulture as a Senior Content Producer / Presenter in 2023. He started his own podcast, We Love Dad Movies, in 2022, and has contributed several written pieces to the Eisner-nominated comics website Shelfdust as well.
In his current role, Ewan incorporates his love of cinema, comic books, and history into written pieces and video essays for WhatCulture's Film & TV channel, as well as WhatCulture Gaming and WhatCulture Horror, with a particular focus on nineties-era Dad Movies, old school Westerns, and Golden Age Hollywood Noir. John Carpenter is his fave, and he thinks Batman Beyond should never have been cancelled. If that's your vibe, you'll probably like his stuff.