Every dev team will have different standards and opinions on how to use Git. Some teams require all pull requests to contain a single commit, while others prefer to see a series of small, focused commits.
If you join a team that prefers a single commit, you will need to know how to "squash" your commits together. To be fair, even if you don't need a single commit, squashing is useful to keep your commit history clean.
It's exactly what it sounds like. We take all the changes from a series of commits and squash them into a single commit.

Let's get ready to squash some commits.
Run and submit the CLI tests.