Since lemmy.ca is federated, you can see content from everywhere. However you also have a lot of control over your feed, and you can either block communities you don't like or (my preference) primarily use the 'subscribed' feed and only subscribe to the content you want to see.
This guide page might help: https://fedecan.ca/en/guide/lemmy/for-users/detailed-overview
If you look on !canada@lemmy.ca, we maintain a pinned post with a list of Canadian communities to subscribe to