Why not make a grey cardigan and black jeans your outfit choice? These items are very practical and look cool when married together. Grey leather low top sneakers will bring a dressed-down feel to your outfit. Take inspiration from ensembles like this if it's time to add maturity to your 20-year-old's wardrobe.
Grey Cardigan with Black Jeans Chill Weather Outfits For Men In Their 20s
This laid-back combo of a grey cardigan and black jeans is a winning option when you need to look cool but have no time to put together a look. As for the shoes, you could go down a more casual route with white leather low top sneakers. This outfit looks great on 20-year-old gentlemen.