[dotnet00]

IIRC a big part of Perseverance's mission is to stash away pristine, provably untouched samples of Mars, because NASA sees a human landing on Mars in the nearish (ie 20-30 years) as an inevitability.

I don't think they'd quarantine the planet due to it, even moreso because even if the US decides to quarantine it, other nations might not and even then, there'd be value to sending a crew to say, a station in Mars orbit or on Phobos/Deimos, for more effective control over survey vehicles and to reduce the feedback loop between retrieving samples from the surface and studying them.