Thanks for the follow-up @Ellen_Duffer
This was actually a request that came from the Community 
and yes, I can confirm that tasks nested within a Section you’re deleting will get deleted too. Sounds like you’re more looking to “Archive” a Section (keep the data, but remove it from your current view), am I correct? If so, I’d highly encourage you ro add your vote to Archive a Section in a Project
Hope this helps!