## 1 Introduction  
Cities are finding new ways to address pressing societal and environmental challenges. Urban shared governance approaches, and models are a key part of the innovation and change needed, as it is now clear that community-led initiatives are critical for success [1]. More research, led by a practice-based approach, is needed to provide support to local authorities as they move to adopt co-created Nature-based Solutions (NBS) [2, 3]. This continued research can lead us in unprecedented directions. For example, there currently seems to be a tendency towards the adoption of bottom-up initiatives in participatory planning, though there is a range in the approaches taken and a new openness of cities to community-led initiatives. New trends and results are beginning to show that urban transformation in spatial planning can and should progress along many diverse, unique pathways [4, 5, 6], including recognizing when moves away from bottom-up actions would be helpful, which can be somewhat counterintuitive.  
This research aims to investigate the various possibilities of governance typologies that were adopted in CLEVER Cities (a Horizon 2020 project which spans from 2018 until 2023) and to document how complex adaptations occur in cities' governance structures over time. Specifically, we analyze the changes in collaborative governance models from the post-processing of the CLEVER Cities experiences in the three frontrunners cities of London, Milan, and Hamburg that helped fertilize the pathways for urban transition and regeneration. In each city, a co-creation process has been initiated with local authorities, municipalities, academia, private actors, civil society, and citizens to support the effective urban regeneration processes that respect each city's context [7]. CLEVER Cities project also has six fellow cities that adopt the urban greening processes of the three frontrunners with less structured co-creation processes.  
An in-depth perspective is given on aspects of shared governance and Urban Living Labs (ULLs), especially those related to large-scale urban regeneration projects that aim to achieve both in-depth local stakeholder empowerment and community-wide involvement [8; 9; 10]. Herein, ULLs are intended not just as a vehicle for place-based urban regeneration but also as a starting point for more collaborative approaches towards shared governance. In response to local contexts, such as existing social structures and local institutional arrangements, different governance models evolved accordingly. Following a Multi-level Perspective [11], within each of the three cities, an examination was made of the range of integrated collaborative governance models that emerged and the changes and adaptations observed at three points in time during the process: at its initiation, mobilization, and at its consolidation phases. The first phase of the co-creation process aimed to establish an Urban Innovation Partnership (UIP), which was comprised of local clusters of stakeholders and formed using some form of partnership. During the co-design and subsequent phases, each city's ULLs' developed their own collaborative governance models based on the specific circumstances encountered.  
Throughout the research materials and methods section, an analysis of the development of the integrated collaborative governance models is explored and then mirrored in the following sections based on the narratives from London, Milan, and Hamburg. We pose the questions: How have diverse pathways moving towards integrated collaborative governance led to more complex and adaptive governance approaches? As well as to what extent do the recurrent models of shared governance from different cities have correlations with their social and spatial contexts in the settings of their respective co-creation processes? In the last section, discussions and conclusions are drawn from the processes of developing integrated collaborative governance frameworks over the three phases.