Hisui is wearing the tank-set that can be obtained in the dungeon "Shisui of the Violet Tides". While her outfit can only be worn by tanks (and therefor can only used by them as a glamour - FFXIV-version of "mog"), all the Shisui-sets look similar with only slight changes in the design (like different kinds of sleeves) and colour.

In addition to that there is the "Faire"-set that was obtainable during the 2018 Moonfire Faire event and is a replica on of the Shisui-designs - its not the tank-one, though, but dyeable and it can be worn by all jobs. I think it should be on the mogstation by now.