I'm on H1B visa, married to a US citizen. I will get a Green Card but in the interim how should i file my taxes; jointly as a married couple or filing separately?

I'm on an H1B visa. Last year I married a US citizen. I have decided to get a Green Card rather than renew my H1B, however before I get my Green Card how should i file my taxes? Can I file jointly as a married couple or because I'm on an H1B do we have to file separately?