To start talking to another Git repo, use “git remote add”. This gives you a short name used to refer to the other repo (called a “remote”).
Use “git fetch” to fetch the branches from that remote. These are now available in your repo as “<name>/<branch>”, and you can “git log” or “git diff” these branches.
To merge one of these branches into the current branch, use “git merge”.
git pull is a shorthand for those two commands, but don't use it if you don't want to merge.