The standard version of the DualSense is white and black, just like the PlayStation 5 itself. The controller differs in this from that of previous game consoles, which were almost all completely designed in black.
The Midnight Black edition that Sony announced today appears to be a reference to those earlier controllers. In the Cosmic Red version, the white panels of the standard controller have been replaced by red ones.
The new variants will be on sale from next month. Presumably they are easier to find than the PlayStation 5 itself, which will likely be scarce until 2022.