Yakuza: Like a Dragon was called Ryū ga Gotoku 7 in Japan, but the number was dropped in the west as it also was something of a reboot with a new protagonist and a brand battle system. We assume Yakuza 8 won't be numbered in the West either (or maybe be called Yakuza: Like a Dragon 2), but let's not focus on that right now.
Instead, Ryu ga Gotoku Studio director Masayoshi Yokoyama has recently revealed during a Famitsu interview that a new installation in the series is brewing, and also shared some details. Amongst other things, he confirmed that the next game will still have Ichiban Kasuga as the main protagonist, but it will take place several years after Yakuza: Like a Dragon. He also said this regarding the Judgment series: "We will continue to cherish the Judgement series."
Finally, it was also revealed that Ryu ga Gotoku Studio is also developing other projects not related to Yakuza or Judgment, but what this means is entirely up for speculation.
Thanks ryokutya