I think Mr. mosh said something wrong in the course in collaboration section in pushing video at 1:48.
He said that we can pull then merge or rebase to solve issues that may happen when pushing
I think he mean fetch then merge as pulling already do merge as explained in the course.
He may have misspoke. A pull means fetch and merge (unless you’ve changed the behavior of pull to do a rebase instead). A fetch will only bring the content from the remote and update your local “remote” branch (which you probably have named origin or something similar).