The public cloud guarantees low costs and is suitable for all applications. Resource utilization improves, with variable scaling. All services can be reached from any location.
The risk of threats is much lower than in the private cloud due to the high Microsoft security standards.
The combination of a public and a private cloud makes sense, in case of very large data sets that must be processed directly on premises, or in case of high security requirements, where splitting up records in the cloud and on premises produces unusable data fragments. Costs incur for the cloud and for the local infrastructure.
A private cloud is operated on premises. In contrast to conventional server landscapes, local cloud services bring a good flexibility. However, the infrastructure and security costs are completely on the operator side,
and overcapacity cannot be shared.
Existing server infrastructure can be successively moved to the cloud. A good timing is, when servers have to be replaced, or if the server capacities have to be significantly expanded due to increased consumption.
A gradual shift to the cloud is possible in most cases.