It is not clear at this time how the agreement will be implemented, but as far as the official announcement is concerned, Huawei now has an alternative to Google Maps.
The Chinese smartphone maker has stepped up efforts to develop and rollout viable alternatives to Google Mobile Services and apps since the US government placed it on a list of banned companies. This ban means that Huawei cannot use Google Maps and other Google products anymore in its new phones. The deal with TomTom means Huawei can develop apps using TomTom maps, information and services in general. Source
