git stash pop vs git rebase
The stash is meant to store changes that are not meant to be commited yet. For example if you are working on something that isn't done yet, and you want to work on something else for a while without committing the unfinished work, then you use a stash to store it for later use.
If you however have actual commits, that contain finished work, then use either git merge or git rebase to merge/rebase those commits into the history.