SAP CRM, S/4HANA Service & S/4HANA Sales, C4C - which application to use and when?

With the expansion from on-premise to cloud solutions, SAP's portfolio has grown steadily. This has not stopped at the "Sales & Service" area, and reactions from prospects and customers here are as broad as the portfolio itself.
The question that arises is, "Which of these solutions is right for my needs?" When asked about this by consulting professionals, often the response is, "It depends ..."
Understandably, that's not the answer you want to hear. So in the next section, I'll give a brief outline of each application (CRM, S/4HANA Service, S/4HANA Sales, C4C) and hope that this will give you a good top-down view of SAP's "Sales & Service" portfolio.

With the "view from above" shown, I would now like to discuss the applications listed:

SAP CRM

CRM 7.0 EHP4 is the current version that is expected to be supported by SAP until the end of 2027. It is an evolved software that is on the market as an on-premise solution. The software runs stably and makes a good impression with its standard interface to the SAP system (backend system).
The positive experience that customers appreciate does not make it easy to pivot to a new solution, namely SAP S/4HANA Service & S/4HANA Sales.

SAP S/4HANA Service & S/4HANA Sales

When we talk about new here, we mean that a very large proportion of the previous CRM solution has been transferred to S/4HANA Core.
The advantages here include:

• Elimination of the interface to the on-premise system
• Approx. 80% of the CRM world in S/4HANA Core
• Known process flows and contents can be thought through further
• Investment protection of customer developments
• One-document philosophy for sales and service was adopted
• Speed and direct integration into tangential S/4HANA processes

Working with the Fiori Launchpad enables end-to-end processing of service and sales processes as well as other lines of business and thus does not require any major training effort.
If users work with the familiar defined roles, this is also still possible, as shown in the following image for the "Service IC Agent":

Service as well as Sales can be used in S/4HANA Cloud or On-Premise.

SAP C4C (Cloud for Customer)

The third application, SAP Cloud for Customer, is a pure cloud solution. SAP C4C is part of the Customer Experience Suite (CX or C/4HANA) and consists of the SAP Sales Cloud and SAP Service Cloud solutions.
SAP C4C is presented in such a way that it is itself the front-office application and the S/4HANA Core is the back-office application. In this case, the C4C components take over activities from the previous CRM environment or in combination with S/4HANA Service / S/4HANA Sales.
This sounds quite complicated at first, but basically it can be separated quite well. Everything concerning the daily business with the customer is handled in the front office. The new interfaces make it possible to work quickly and conveniently. For example, the targeted addressing of customer needs can be achieved through the use of multi-level campaign processes, sales optimization through the use of predefined or customized dashboards, and the integration of web services.
The interface settings in general as well as the user-related interfaces are much easier to set than previously known from the ERP or S/4HANA world.
Here is a little insight:

The presentation can also be made even leaner with little effort.
The back office then takes over the financial part, e.g. the billing of services or the processing of sales

What combinations are possible?

The picture at the beginning of this post outlined the view from above. In the following, I would like to show how SAP sees the transitions from today to tomorrow, when the SAP CRM solution has been in use up to now:

Before concluding, here again is a tabulation of what and when: