If you're new to comics, comic book movies, superhero history, you might not already know, no one dead ever stays dead, even those given the grandest most emotional sendoffs.
I don't understand why Wolverine in Deadpool 3 was ever a matter of debate when Deadpool 2 literally ended with Logan's death being undone. It may have been a joke at the time, but now the joke got a sequel, so let's just roll with it.