SAP HCI is developed as Integration System-as-a-Support (PAAS) which helps you to combine various unbiased systems/applications for a business method. HCI can do Cloud to Cloud, Cloud to On-premise, On-premise to On-premise and Hybrid model. HCI gives Adapters (Connectivity possibilities) for instance: Cleaning soap Adapter, IDoc, HTTP, Mail, SFTP,Ariba, oData. https://paxtonwslgz.bloggazza.com/27774540/hana-cloud-integration