You cannot file Joint for 2020. Does the company that sent the retirement money know that he passed in 2019? If so, then the 2020 1099-R belongs to your husband's Estate, which may require the filing of Form 1041.
OR they issued the 1099-R under his name and Social Security number when they should have issued it under your name and Social Security number. I recommend contacting the payor ASAP.
all you have to do is report the income on your own tax return.
Put it under other income -" Income in respect of a decedent".
True, but then you get into a correspondence loop with the IRS when they run their matching programs, and we know how the Service is handling correspondence right now--as in, months if not a year or more behind.
IN MY OPINION ONLY, it's best to get a corrected 1099-R and report the income under Pensions.