I am a Pakistani passport holder, and a permanent resident of Canada, with PR card. Travelling via Frankfurt by Air Canada. Can I visit the city during this 8-hour layover or does it require any formality?
As a Pakistani citizen you would need a Schengen Visa to enter Germany. As a Canadian resident you can apply for it at a German consulate in Canada, but you still need a Visa. https://www.schengenvisainfo.com/germany-visa/canada/