Google Analytics 4 (formerly known as “App + Web”) is a new kind of property, with several advantages over Universal Analytics: 

• Privacy-focused and durable for the future 
• Intelligent, using machine learning to unearth insights about the customer journey across platforms and devices
• Enhanced, seamless integrations with Google’s advertising platforms to optimize campaign performance and drive greater marketing ROI

source : https://support.google.com/analytics/answer/10089681