A common point of confusion is SAP Integration Suite vs CPI. CPI (Cloud Platform Integration) is the older name for what SAP now calls Cloud Integration, which is the core capability for building and running integration flows between systems. SAP Integration Suite is the wider package on SAP BTP that includes Cloud Integration as one of its capabilities, together with others such as API Management, Open Connectors, Integration Advisor and event-based messaging. So the simple answer is that CPI is a part of Integration Suite, not a separate competing product.