One of the Presentation by Fields Gaming & Entertainment says that Tsuburaya has planned a Ultraman TV Series in 2017 & a Movie in 2018 which is aimed for Adults. This series could be the related to the Trailer "ULTRAMAN_n/a".
Well by speaking of Adult aimed Ultraman Series there was Ultraseven X & Ultraman Nexus (→ Ultra N Project).
Other than this every year there will be a TV Series & Movie aimed for Kids & Teenagers. So, Ultraman Fans there is no more fear of "Ultraman Series will end soon" which happened during the time of Ultraman Mebius.
Tsuburaya is also planning a Non-Ultraman TV Series for 2017 & also a movie.