I guess you are asking about Sessions collections. If you are the collection owner, then the deletion is permanent - the deletion process is asking for an explicit confirmation (via a prompt) before the actual deletion happens.
However, if you are not the owner and the collection wa\s shared with you, you could recover it from the Shared Sessions button.
The same is applicable for Requests collections.
1219787539
i delete my collections ,how to recovery collection that is deleted by mistake?