A: Never. Microsoft has no plans to release games for PSP. The PSP is a discontinued console.
Since the "Forza Horizon 5 PPSSPP ISO" is a myth, here are the actual ways to play FH5 on the go: forza horizon 5 ppsspp iso file top
: Open the emulator, navigate to your "Games" tab, and select the folder where you saved the ISO. A Note on Safety: A: Never