Oops, just posted a similar response in the other thread.
Yes, zombies have a chance to evolve over time. I’m not 100% on the new evolution system, but it used to be that there was a list they could evolve into (thereby giving them a chance to evolve into basically the same creature, negating evolution) after a certain amount of time has passed.
Most creatures won’t evolve for quite a few weeks. You’ll start to notice tougher zombies around autumn/winter in the first year. And any of the scenarios that start you in year 2 often end up having a lot of hulks/corrosive/skeletal juggernauts pretty quick.