SAP HCI is made as Integration System-as-a-Company (PAAS) which really helps to combine many unbiased devices/apps for a business approach. HCI can perform Cloud to Cloud, Cloud to On-premise, On-premise to On-premise and Hybrid design. HCI delivers Adapters (Connectivity selections) for instance: Cleaning soap Adapter, IDoc, HTTP, Mail, SFTP,Ariba, oData. https://s4-hana-cloud-faq24680.dreamyblogs.com/28520931/hana-cloud-integration