The biggest obstacle is probably how scarce water is on Mars. Like this desert moss might survive for a while but without water it won't be able to reproduce and spread. The team in the link above is considering genetically engineering an organism to absorb water from the atmosphere but even then it is just trace amounts.
Life requires water to survive and grow, doesn't seem like you can have a living organism terraform Mars for you unless you've introduced a ton of water through other means.
The biggest obstacle is probably how scarce water is on Mars. Like this desert moss might survive for a while but without water it won't be able to reproduce and spread. The team in the link above is considering genetically engineering an organism to absorb water from the atmosphere but even then it is just trace amounts.
Life requires water to survive and grow, doesn't seem like you can have a living organism terraform Mars for you unless you've introduced a ton of water through other means.