@jules7970
If you hold US citizenship you are required to file a US tax return annually no matter how long you have been out of the country.
Basic information here:
https://www.irs.gov/individuals/international-taxpayers/taxpayers-living-abroad
I presume you are also filing Canadian Tax Returns, there are all kinds of rules that apply in this situation that help avoid double taxation. Canada and the US have reciprocal tax treaties so taxes you pay in one country can be used as a credit against taxes you pay in the other.
This is beyond the scope of my knowledge, you may need advice from a tax professional but I would start looking online as there are more than a Million US citizens in Canada and they all have to deal with this.
The IRS has or had a couple of Amnesty Programs for ex-pats who have not filed and have outstanding returns.

"What else could I do? I had no trade so I became a peddler" - Lazarus Greenberg 1915
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