I thought this was already a done deal.
http://www.businessinsider.com/nasa-mars-2020-mission-step-toward-first-mars-sample-retrieval-2017-12
Apparently the robot will have a biotype search and destroy mission. Well not destroy, just search, remove, put in a canister, put it on this big explody thing, send it on a mission in the cold deep of space, then burning into earths atmosphere, landing but . . . . .not destroy.