You can lose your permanent residency status in Canada for various reasons:
If you become a Canadian Citizen.
You can renounce your PR status if you no longer want to live in Canada or you haven't lived in Canada enough to keep your permanent residency. In the last five years, you must have been in the country for at least 730 days, although they don’t need to be continuous.
You become inadmissible to Canada for committing a crime, for security reasons or violating human rights.