git pull =
git fetch +
It’s always perfectly safe to do a
git fetch and it won’t change your local repository.
But when you run
git pull, Git will also try to intelligently perform a
git merge - and in the process, it will merge all the upstream commits without asking you to individually verify them.
Here’s a good chart to help you understand what happens when you run each of the most common Git command:
Source: Oliver Steel’s blog