....well....No if you stopped working for them in 2020, because you should still get a W-2 from them.
....maybe if you stopped working for them in 2019....i.e. Yes if they will not issue a 2020 W-2...or perhaps No, not if you worked right up to the end of 2019...because sometimes the last week of 2019 work can end up on a 2020 W-2 form...and you would end up having to declare that as 2020 income.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
