The person, label or item is doing exactly what you expected in terms of fashion trends.
So if lace dresses are popular, they are making or wearing lace dresses. You may wonder why we keep using such phrases if we realise some of them are so annoying. Well, you try coming up with 20 synonyms for fashionable and you'll understand.
Use it: There were some weird bits, but mostly her whole collection was so on trend.
Source: NZ Herald News