git fetch updates your remote-tracking branches under
refs/remotes/<remote>/. This operation is safe to run at any time since it never changes any of your local branches under
git pull brings a local branch up-to-date with its remote version, while also updating your other remote-tracking branches.
From the Git documentation for
git fetchwith the given parameters and then depending on configuration options or command line flags, will call either
git mergeto reconcile diverging branches.