Summary
- The official timeline book of the Marvel Cinematic Universe confirms that Agents of SHIELD is not considered canon after Phil Coulson's death in The Avengers.
- Kevin Feige acknowledges that there are Marvel stories that are canonical to the multiverse but not the Sacred Timeline.
- The timeline in the book specifically focuses on the MCU's Sacred Timeline up until Phase 4, disregarding any events or storytelling from Agents of SHIELD.
One of the biggest Agents of SHIELD gets addressed. Despite having been initially created as being part of the main MCU timeline, Agents of SHIELD never got to engage with the Marvel Studios movies, even though the ABC TV show had a direct impact in films like Avengers: Age of Ultron. Because of that notion, it has been questioned for years whether or not Agents of SHIELD is actually canon to the MCU.
In the new book, Marvel Studios The Marvel Cinematic Universe An Official Timeline, the Agents of SHIELD situation is addressed as the entirety of the MCU Phase 1 through 4 are covered in immense detail. The Death Of Phil Coulson discusses Coulson's heroic sacrifice and death in The Avengers, but nothing of his resurrection or his team in Agents of SHIELD is mentioned or even hinted at. However, there's hope for the team in the future, as Kevin Feige gives the following quote in the book's forward:
On the Multiverse note, we recognize that there are stories - movies and series - that are canonical to Marvel but were created by different storytellers during different periods of Marvel's history. The timeline presented in this book is specific to the MCU's Sacred Timeline through Phase 4. But, as we move forward and dive deeper into the Multiverse Saga, you never know when timelines may just crash or converge (hint, hint/ spoiler alert).

10 Things Agents Of SHIELD Did Way Before The MCU
In seven seasons of Agents of SHIELD, the Marvel Television series featured several storylines that would later be included in the MCU proper.
How Agents Of Shield Could Still Become Retroactive MCU Canon
While Feige's quote may put an end to the Agents of SHIELD debate, for the time being, the Marvel TV show could still become canon retroactively. In Marvel Studios The Marvel Cinematic Universe An Official Timeline, Feige's forward also came with the following: "But, as we move forward and dive deeper into the Multiverse Saga, you never know when timelines may just crash or converge." Even though he doesn't flat out say it, Feige is casually hinting at the larger endgame for The Multiverse Saga, which is Avengers: The Kang Dynasty and Avengers: Secret Wars.
With Avengers: Secret Wars being rumored to lead to a soft reboot of the MCU, it is entirely possible that Agents of SHIELD, as well as a lot of other Marvel TV shows will become part of the main MCU timeline. It is also worth ing that one of the reasons why Daredevil: Born Again is starting over from scratch is because, supposedly, the Marvel Studios executives wanted it to be more like Netflix's Daredevil TV show, which is a very interesting notion despite Feige considering those shows outside his main canon. Time will tell if any Agents of SHIELD characters will show up in Phases 5 and 6, but the door definitely doesn't seem to be entirely closed on that idea.
Feige's forward and the lack of history for Coulson in Marvel Studios The Marvel Cinematic Universe An Official Timeline is still a bit comedic, considering how much he was confirming that Agents of SHIELD was canon to the MCU all those years ago. With Coulson even starting out as an MCU character, the fact that it has led to this is bound to be questioned by long-time MCU audience . Canon or not, the world can still relive every season of Agents of SHIELD on Disney+ and through Blu-Ray/DVD.
Source: Marvel Studios The Marvel Cinematic Universe An Official Timeline