So you cannot do anything or make any program run in the background when Sleep mode is initiated.
This way, your PC draws a minimal amount of power to keep just the memory device on. And while this happens, all the PC components are powered off except the memory. When sleep mode is activated, all the settings, programs, and documents open on your PC are moved to its memory device.
How to Disable Auto-Sleep mode in Windows 10 Can I continue downloading in Sleep Mode on Windows 10?