Samsung was a bit late to the party with its first PCIe Gen4 SSD for client PCs — the 980 Pro — and lost some market share to Phison and its partners. However, the firm does not want to be late with its PCIe Gen5 drives for enthusiast-grade drives, which is why its next-generation 990 Pro SSDs are already listed in the South Korean customs database.
Samsung's 990 Pro SSD entry in the customs database (discovered by @Harukaze5719) does not reveal many details about the upcoming drives except their model numbers (MZ-V9P1T0, MZ-V9P2T0) that possibly point to 1TB and 2TB configurations. 1TB and 2TB capacities are not the highest capacity points for M.2 drives these days, yet they indicate that the forthcoming Samsung 990 Pro SSDs will not target entry-level PCs.
Processors supporting a PCIe 5.0 interface have been shipping for a little less than a year, and this fall, more CPUs with PCIe support will be available from AMD (codenamed Raphael) and Intel (codenamed Raptor Lake). So, it hardly makes sense for companies like Samsung to release another generation of premium drives with a PCIe 4.0 interface. Therefore, it is safe to assume that Samsung's next-generation 990 Pro SSDs will feature a PCIe 5.0 x4 interface.
In fact, Samsung has been shipping its PM1743 enterprise-grade PCIe Gen5 SSDs for a while now, but given their positioning, such drives are expensive and are overkill for a desktop PC. Furthermore, since they come in an E3.S form-factor, they need a special adapter for desktops. Therefore, very few enthusiasts used them with Intel's 12th Generation Core 'Alder Lake' systems.
By contrast, Samsung's 990 Pro SSDs are expected to use an M.2-2280 form factor and therefore be compatible with desktops and laptops. The only thing that is not clear is how much heat those drives emit and what kind of cooling system they require.
Keeping in mind that the South Korean customs database already lists Samsung's 990 Pro SSDs, expect them to be available rather sooner than later. Unfortunately, we have no idea how much Samsung will charge for those products.