@ gur1, generally speaking, even if your spouse has moved to another country for US tax purposes you can still file jointly as long as you expose her world earnings to US taxes . In such a case depending on the exact facts and circumstances, her foreign income could be eligible for exclusion from US taxes ( up to a max set each year --- foreign earned income exclusion ).
Please tell me more --- your citizenship, her citizenship; does she work in Canada for a local entity or remotely for a US entity or for US govt; what work visa do you have and she had ; is her US visa terminated; do you own home here in the USA etc. etc.
I will circle back once I hear from you
pk
