I had lived in Canada for over 20 years since 1998, and have been outside of Canada for less than 2 years, about a year & a half.How long have you been outside Canada? You have to be living in Canada for at least 2 years during the last 5 years. That's what is called residency obligation.
Note that once you leave the US, you will be automatically banned from entering the US for 10 years. Once you leave, make sure you don't try returning for the next 10 years.If I overstay in the US for over a year and return to Canada b4 my PR card expires, Will it affect the renewal of my PR card?!