Considering the game is still over 7 months away from release (It was recently delayed, if you were not aware), no one can say for sure at this point. As far as I know, they haven't even released official system requirements for it yet.
The capability of your graphics card will depend heavily on what resolution you will be using. Based on other compararable game releases, at 1080p resolution it will likely run the game quite well, and I would expect it to also run pretty well at 1440p. For 4K resolution, you would likely need to lower the settings a fair amount to get smooth performance though.
There's also raytracing to consider, and with optional raytraced lighting effects enabled, you would likely need a graphics card with raytracing acceleration just to get playable performance. Nvidia's 20-series cards might manage playable performance with raytraced effects enabled at 1080p, but I suspect the upcoming 30-series cards will handle that a lot better. If you want to run settings maxed including RTX, I would probably hold off on a graphics upgrade until closer to the game's release, when those future cards are likely to be out.
As far as the CPU goes, it's difficult to say for sure, as some games want more than four threads for optimal performance these days, and I would guess that's likely to be the case for a more open-world game like this. Again, there's no telling for sure how the game will perform on various hardware until it comes out though.