With a canadian PR alone, you cannot work in the US.
You will need the visa that Non-US citizens/Non-US permanent residents/Non-Canadians/Non-Mexicans need to work legally in the US. Quite a few of those are available depending on your occupation.
In case you become a Canadian citizen later, NAFTA (Canada, US and Mexico are signatories) lets certain professional classes to work in each others' countries on a TN visa. These are valid for a year and renewable.
Hope it helps.