KB article: OneDrive for Business information on limitations
OneDrive for Business works with Sharepoint or also called the Cloud or also known as O365. There are a set of limitations that are noted in KB article:
Restrictions and limitations when you sync SharePoint libraries to your computer through OneDrive for Business
https://support.microsoft.com/kb/2933738
In addition, there is specific Sharepoint Online (also known as Cloud or O365):
SharePoint Online: software boundaries and limits