Hello! I hope whomever reads this is healthy and had a great new year!

I live in Chicago and have made a commitment to being active in the winter instead of my usual hibernating. While I will walk indoors on a treadmill if necessary, I would prefer to do something outside, even though temperatures are low. I would like to know what the best winter workout gear would be for temps as cold as 0 degrees. 

I mainly walk about 4-5 miles a day to get at least 10K steps in but sometimes I'll jog/run. I do have some baselayers and then some merino wool quarter zips to layer. Currently, I'm just wearing a winter jacket as the outer layer but I was wondering if there is anything better. I hear great things about the Mizuno Thermo=jacket but that may also be more for people who run instead of walk. 

As far as bottoms go, I usually wear an UnderArmor cold gear legging underneath some sweatpants. Again, if there's anything better I'm all ears. 

I'd also like any accessory suggestions (hats, gloves/mittens, etc.) if possible. 

Thanks for your time!