Andynd1uk said:
some employers may ask for it as proof of permanent residency
By the way, employers CANNOT ask for your PR card as proof of permanent residency. In fact, they cannot ask you for any visa proof. All they can do is ask you during the interview process if you're legally authorized to work in Canada. If they give you an offer, they will obviously ask you for your SIN number, which you have to inform. That's about it. If they ask you for proof of immigration or citizenship before giving you a job, this could be interpreted as discrimination (which is illegal).