The aim of PROMISCE is to provide the foundations for a novel research field: propagating quantum microwave technologies in strongly and ultrastrongly coupled environments. In particular, its potential for scalable quantum information and communication technology (Q-ICT) applications will be demonstrated. PROMISCE is born from a challenging and controversial idea, which is that microwave photons can interact strongly among each other and with their environment even in the absence of confining cavities.PROMISCE combines two major innovative and interdisciplinary components. The first one, propagating quantum microwave photonics, focuses on the generation, control, and detection of quantum microwave beams and photons using superconducting quantum circuits. The second component aims at exploring propagating quantum microwave interactions. Novel paths in engineering strong and ultrastrong controlled interactions between propagating microwave photons and their environment, and among photons themselves, will be pursued. To this end, we will employ superconducting quantum circuits and develop sophisticated quantum metamaterials. We note that both components are intimately connected: technological and conceptual achievements in one component will immediately trigger progress in the other one. Together they will provide, integrated on a chip, the equivalent of optical Q-ICT experiments in the microwave regime.PROMISCE represents a complete paradigm shift beyond the common interest in superconducting qubits for Q-ICT to the concept of encoding quantum information in propagating microwave photons and using an (ultra-)strongly coupled environment as the basic tool for their manipulation. In this context, PROMISCE also introduces a new understanding of the term "environment". Instead of being seen as a source of decoherence or noise, it is converted into a powerful tool for control, communication and information processing.