According to the Mirror quoting Kick off, Arsenal want to buy Felipe Luiz in the winter window.

Felipe-Luiz had previously been associated with Greater Paris, but Greater Paris eventually signed Bernat because Atletico was asking for too much for Felipe. The Brazilian's contract expires next summer, but Atletico still asks for £27 million.
However, Arsenal have big concerns at left-back in the new season, with injuries to Kolasinac and Niles leaving Emery with only Monreal an option.
Atletico will then accept offers of less than £27 million to avoid players leaving for free next summer.