Key features SP2019

• Modern Sites, Pages, Lists, and Libraries
• Team News
• SharePoint Home
• Communication Sites
• OneDrive Sync Client
• Improved hybrid support and scenarios
• New developer options
• Improved support for business process with PowerApps and Flow

New SharePoint framework Spfx can also be used in SP 2019

https://blogs.technet.microsoft.com/christianheim/2018/07/24/sharepoint-2019-public-preview-generally-available/