The digital transformation of public administration requires a profound rethinking of the relationships between levels of government in multilevel systems. Italy's digitalisation process requires State, Region, and local authority cooperation to ensure sustainability, interoperability, and inclusion. The framework aims to create a new national digital ecosystem based on complementarity, data sharing, interoperable infrastructures, and platforms supported by national and European financial mechanisms. This cooperation fluctuates between peer-to-peer and more centralised forms of coordination, when the central State's exclusive competency in information coordination and financial mechanisms reemerges. The municipal dimension, with structural efforts and functional, occasional coordination, is growing alongside the State–Region axis, risking a two-speed digital Italy. German federalism has a constitutional basis for digital cooperation and coordination tools, but operational fragmentation, delays in service digitalisation, and Länder autonomy constraints make it similar and problematic. Overall, a transforming cooperative model emerges, which must balance autonomy and coordination, efficiency and participation, with the aim of creating a truly integrated digital ecosystem capable of supporting innovation and territorial cohesion.