Phil Coulson was still a relatively important character in the first phase of the Marvel Cinematic Universe.
Although he was killed by Loki in Avengers 1, in fact, he was out of a state of "dead, but not completely dead".

Later episodes in the Agents of S.H.I.E.L.D. series brought Coulson back to life, allowing him to continue his adventure with a group of agents.
There is also a young Coulson in "Captain Marvel 1".
So although there are not many later scenes, Coulson's presence in the film universe has always existed.
In Infinite Possibilities: What If, Curzon also returns.
Recently, there are rumors on the Internet that Coulson will return in the Marvel Cinematic Universe.
Clark Greg echoed the rumor in an interview with Entertainment Weekly.
He began by saying that he had indeed heard the rumor, "Yes, I have heard it, and I follow it closely like a fanatic." ”
But in response, Greg only said, "I've heard these rumors, and that's what I'm able to respond to." I did hear these rumors. ”
It's worthy of the old Marvel people. Greg's response can only be said to be, listening to Jun's words, as if listening to a seat.
But if Greg does come back, the next Episode of Invasion will be the best chance.
Because the show has Nick Fury and Talos, and it's closely related to Captain Marvel 1, and he happens to be in this movie.
"Secret Invasion" is not yet finalized.