The paper proposes some reflections resulting from the author’s ongoing research activities on Green Infrastructure and Ecosystem Services, which, when integrated into urban planning, can improve the supply of goods and services for the well-being of society, by incorporating the ability to adapt to current risks and future climate change, reducing the ecological footprint and ecological debts, while improving resilience, health, and quality of life, and leaving no one behind, in line with the UN 2030 Agenda. Despite the relevance of the topic and the critical feature of the “time factor” in addressing a climate crisis requiring urgent responses and far-sighted policy choices, and the numerous international documents and commitments, scientific advances have not yet produced adequate operational impacts, which are fully integrated and widespread in policies, strategies, and actions at a local level, in order to move towards the necessary ecological transition in the perspective of integral ecology. Nevertheless, in the EU scenario, there are many interesting experiences aimed at an ecological transition that goes beyond the technological and energy transition and concerns foremost the climate issue and the exit from the fossil fuel system, but also the dramatic loss of biodiversity, conflicts over access and use of resources, the international geopolitical instability, and profound economic and social inequalities. In this ongoing process, cities are drivers of innovation and, through the selected case studies proposed later in this paper, it is possible to highlight the lessons learned in terms of critical and/or success factors; identify some guidelines to adapt possible solutions to the specific issues to be addressed in different contexts; suggest future research and in-depth perspectives.