The advent of 5G introduces the concept of network slicing which is meant to permit network service providers to overcome the great challenge of forthcoming 5G services: how to support and operate different kinds of services with very distinct needs onto the same infrastructure. Deploying altogether on the same network makes it quite difficult to define a common architecture capable of keeping the diverse requirements of all of them. The network slicing concept foresees a number of logically independent slices, each comprising different network nodes and service functions, which are interconnected and are involved in the delivery and the operation of a specific service. By instantiating network slices, the network will be able to provide completely different services in a dynamic way over the same infrastructure. This chapter overviews the challenges raised by the implementation of the network slicing concept and which will be faced by the network operators.