Final Cut Pro is developed by Apple. Just like iMessage and GarageBand, Apple keeps this software exclusive to its ecosystem (macOS). Apple has never released a Windows version, and industry insiders say they never will.
While there is no direct download, technology has advanced enough that you can technically run Final Cut Pro on non-Apple hardware. However, it is not for the faint of heart. This involves creating a "Hackintosh." final cut pro windows download