Temporary work visa allows you to work in Canada temporarily. PNP allows you to get permanent residency. Some PNP's do not require you to have a job offer, for example if you are sponsored by family or you come in on the H1 program in AB. If you have a job offer, you can either apply directly to the PNP with your employer or you can come in on a temporary work permit and apply for PNP later. Some employers will not apply for a PNP for an employee right away, they may want you to stay with them through your probation period so they know if they want to keep you first. Getting permanent residency through PNP can take from 6-15 months in Alberta, probably similar in other provinces. If you leave your employer before you get your PR, your application would be cancelled and you would have to start again with a new employer. Another option to apply for permanent residency would be to work for 2 years and then apply for PR through Canadian experience class. You would not need your employers help for that.