"They both have green card."  One crucial factor: Green card dates and their presence in the US in the year they got the green card.  

If they got the green card in 2021, See  https://www.irs.gov/individuals/international-taxpayers/residency-starting-and-ending-dates

Green card holders are subject to worldwide income and pretty much all the general tax regulations.  A residency on foreign soil would make a difference for federal tax in only a few issues such as Foreign earned income exclusion...  FBAR is also applicable to green card holders.