There are new rumors floating around that say a new Space Marine Codex is coming in 2019 and along with it a series of Primaris Marine releases. Of course these are rumors, and I will let you decide.
Please remember that these are rumors and do indeed require some salt.
via Bols
http://www.belloflostsouls.net/2018/11/40k-rumors-codex-space-marines-2-0.html
Industry Professionals Say: New Codex Space Marines Slated for 2019
Will include a number of new kits for Primaris Marines:
- A unit of high speed 1-man vehicles
- A Primaris Medium Transport
- A Primaris small Flyer
- A Primaris vehicle variant with new large turret weapon options
- A Primaris Heavy Infantry unit with Assault Terminator weapon equivalents.