As part of a four year plan outlined a while ago to CD Projekt RED investors, the studio outlined plans to release both Cyberpunk 2077 and an as-yet unannounced "AAA RPG" by 2021. In a recent forum post (translated from Polish) it confirms that its plans remain unchanged and that two massive RPGs are in development - with both due within then next two years.
With no firm release date or window for Cyberpunk 2077, and CD Projekt RED stating that it firmly knows what goes into the making of a new AAA title, this statement is the current plan and not a guess or speculation. With the lid mostly lifted on Cyberpunk 2077 when it comes to gameplay and how it looks - CD Projekt RED is remaining tight lipped about the mysterious new "AAA RPG".
Which one could speculate could be a return to the world of The Witcher - sans Geralt. Or something new entirely. With 2021 not all that far away, one would also assume that the plan would be to spread the release dates of two huge games on the horizon out a bit. Which means that Cyberpunk 2077 could be closer than we think, or at the very least on track for a holiday 2019 release.