SAP HCI is designed as Integration Platform-as-a-Provider (PAAS) which helps you to integrate several independent techniques/programs for a business method. HCI can do Cloud to Cloud, Cloud to On-premise, On-premise to On-premise and Hybrid product. HCI features Adapters (Connectivity options) such as: Cleaning soap Adapter, IDoc, HTTP, Mail, SFTP,Ariba, oData. https://sap-s-4hana-cloud71358.thelateblog.com/28732844/hana-cloud-integration