Latest rumors go that Loeb is signing with Hyundai or Ford for the 2019 WRC season. Most likely Hyundai though.
Source
It would be a total disaster if PSA let this man go. Baffling really

Understable that Citroën can't take the risk to give a seat at Loeb when signing Ogier. It has nothing to do with a sponsor that pulled back but more that it won't go down nicely if both champs run for the team. Now they have a 9 times world champion who has been linked to PSA all those year probably running for another team. I am without words...bloody annoying..
Other option I came to think of since he will run Dakar 2019 with PH-Motorsport, an entry in WRC with this private team could be a possibillity but that is speculation on my part.