Clark Gregg's Phil Coulson hasn't been in the MCU for some time. However, It sounds like the multiverse could strike again shortly and facilitate his potential return.
During The Avengers, Clark Gregg's Phil Coulson was killed by Loki, a moment that brought the Avengers together and solidified their bond. Coulson was brought back to life via the T.A.H.I.T.I project in Agents of Shield, but the show is not canon in the MCU. At the moment, Agent Phil Coulson remains dead in the MCU. However, recent comments from Gregg could suggest that Phil Coulson will return to the MCU's continuity.
Speaking with Cosmic Circus at Motor City Comic Con 2023, Gregg said about his return as Phil Coulson, "There's always a chance." When asked to elaborate, Gregg kept it simple. "There’s just always a chance that- I mean, you know, it’s a multiverse," he said. While not a confirmation of his return, his comments suggest Gregg's entertaining the possibility that he could return as the head of S.H.I.E.L.D. and Nick Fury's right-hand man.
Later on in the interview, Gregg was asked if Coulson appears in the upcoming Marvel Studios show Secret Invasion. Gregg mostly talked around the question, at first seeming unaware that Secret Invasion was being released soon, then jumping at the chance to debate if the fact that a Skrull was impersonating Coulson in Captain Marvel meant that Coulson was never truly human and was always being impersonated by a Skrull. Gregg ended the line of questioning by theorizing why Coulson was so popular with fans, saying, "...I think he was, what made him, I don’t know what, stand out or connect with the fans was the fact that he was very, very human."
Whether Gregg is playing coy or in the dark about Coulson's future in the MCU is just as much an unknown as when fans will see Coulson onscreen again. With the multiverse bringing in previously thought-dead characters and versions of characters portrayed in non-MCU movies, nothing is off the table regarding who will show up in a Marvel movie.
The most recent movie to shine a light on the multiverse, Doctor Strange in the Multiverse of Madness, utilized the multiverse to bring multiple versions of Stephen Strange together in one movie. Spider-Man: No Way Home did the same thing but with different actors who had portrayed Spider-Man in the past. Fans have even seen different versions of Phil Coulson in the animated What If...? series. So, while Phil Coulson is still officially MIA in the MCU, there is precedent to suggest that he could make a triumphant return. The question is: what version of him will return?
Source: Cosmic Circus