Deadpool & Wolverine

Told that his universe is ending because the man who held it together is dead, he goes looking for a replacement in other timelines.

It is the film where the Fox continuity formally joins the shared one, and it spends most of its runtime as a wake for two decades of films that were made under a different owner and mostly forgotten.

The reunions are the point and they are more affecting than the jokes around them. It assumes you have seen a great deal, and it is honest that it does not care if you have not.