Azure AD Connect Cloud Sync is a new product recently made available from Microsoft to synchronize objects from On-Premises to Cloud. Azure AD Connect cloud sync helps simplify and automate the management of Azure AD users, through cloud-managed rules for synchronizing those users from existing AD forests.
Below are some essential resources to know more on this product.
Access here: Azure AD Connect Cloud Sync Overview
Another great video from Travis Roberts below on the key differences
Official documentation covering all updates: Azure AD Connect cloud sync documentation