In Attack on Titan 2, your squadmates can appear in their Civilian Clothes costumes. This allows people to see a different side of various people. While past videos showed what Eren, Conny, Krista, Levi, Sasha and Ymir looked like in their more ordinary outfits, the latest one looks at Armin and Mikasa.
As an interesting aside, the scarf Mikasa is wearing is rather important. When Eren saved her when they were children, he gave it to her. So, it only seems natural that she wears it in Attack on Titan 2 when out of uniform.
Attack on Titan 2 releases on the PlayStation 4, PlayStation Vita, Nintendo Switch and PC in Japan on March 15, 2018. It will come to the PlayStation 4, Nintendo Switch, Xbox One and PC in North America and Europe on March 20, 2018.