A sample-return from Mars or other location with potential to host life, is a category V mission under COSPAR, as it is unknown the effects of such hypothetical life would be on humans or on the biosphere of Earth.
A sample-return from Mars or other location with potential to host life, is a category V mission under COSPAR which directs to containment of any unsterilized sample returned to Earth. This is because is unknown the effects of such hypothetical life would be on humans or on the biosphere of Earth.