Yakuza Kiwami is actually a remake of the PS2 game on PS4. Released in January of this year in Japan, it was received quite positively by gamers here.
The good news about the Western release of Kiwami is that like the prequel Yakuza 0, it will also feature the original Japanese audio with localized subtitles.
As for Yakuza 6, that is released in Japan this December 8th for PS4. Starring people like Takeshi Kitano, it has some serious pedigree behind it. Again, the fact we will be getting this game as well, in early 2018, is both wonderful and surreal.
I say surreal because since the first game was released on PS2 back in 2005, the series has never really been properly supported in the West. However, it seems that what with the PS4 library the way it is, Sega is finally doing the right thing and making these games available globally.