The comedian and Catastrophe star appears around the same time as Reynolds, popping up as CIA Agent Loeb. Rather than having to convince Hobbs of the new mission, he's tasked with swaying Shaw to help out (right after he visits his mother in prison, we might add — Loeb apparently isn't great at timing!).
While he might not be as recognizable as Reynolds and Hart, his appearance in the film shouldn't come as a surprise, either — he costarred with Reynolds in Deadpool 2, which was directed by Hobbs and Shaw's David Leitch. It all comes full circle!