Canada has a capital gains exclusion on a primary residence, so you have no Canadian capital gains risk.
If you sell in USA before moving to Canada there’s no Canadian tax impact at all.
To avoid bureaucratic complications that can arise if you sell while straddling the two countries, you would be wise to execute the sale before you take up Canadian residence, that will remove any Canadian implications. If you sell after moving, there are most likely no Canadian capital gains tax implications but the associated paper work that would be generated if you sell after taking up Canadian residency can be highly annoying and will require a CPA’s assistance.