As for the title match, it is currently scheduled on the FIDE calendar for 9-28 November 2018. According to World Chess Championship 2018 in London? (chessdom.com), from early last month,
The World Chess Championship 2018 is going to take place in London. This is what the renowned Spanish journalist Leontxo Garcia writes for the chess section of El Pais, quoting two “close sources” to the organization of the match. [...] Agon says the decision is not official and other venues are still possible.
Earlier this year we learned,
Oslo has been dumped as a potential host city for the next World Chess Championship, with its arranger and the Norwegian government arguing over the reason why. (newsinenglish.no)
See World Championship, Oslo 2018 (June 2017) on this blog for the announcement by Agon.