SAP HCI is designed as Integration System-as-a-Provider (PAAS) which really helps to combine multiple independent programs/apps for a company process. HCI can do Cloud to Cloud, Cloud to On-premise, On-premise to On-premise and Hybrid model. HCI provides Adapters (Connectivity possibilities) for instance: Cleaning soap Adapter, IDoc, HTTP, Mail, SFTP,Ariba, oData. https://sap-s-4hana-cloud70246.uzblog.net/hana-cloud-integration-42485928