The Xbox Series X is Microsoft's upcoming next gen console, due for release near the end of 2020. During development this had been known as Project Scarlett.
The specs appear to be significant step above the current generation, with features including a 1TB high speed NVMe SSD (Solid State Drive) storage, 12.4 Teraflops of graphical processing power and an 8 core, 16 thread 'Zen 2' CPU and 16GB GDDR6 memory. This combines to allow a console is capable of real time ray tracing, which combined with the fast SSD should be capable of giving us visuals unlike anything we'd seen in the home console space before, additionally it will be capable of providing an 8K video output (at 60fps) or 4K video output at 120fps.
The Series X will be fully backward compatible with the Xbox One - all Xbox One games, including Xbox 360 and Xbox games that are already available on backwards compatibility, will run on the Series X. A feature called Smart Delivery is also being promoted, which allows a game to be purchased once for 'Xbox' and it will then be available on Xbox One as well as with a Xbox Series X enhanced version at no extra cost - although 3rd party publishers are not obligated to support it, all Microsoft titles will support this (to date, Ubisoft and EA have confirmed support).
Expected Microsoft titles for the Xbox Series X are: Halo Infinite, Hellblade 2, Forza Motorsport 8 (expected), Grounded
At present, the exact release date and price are not yet know.