Cancer evades the immune system by generating an immunosuppressive tumour-microenvironment through various mechanisms to enable unhampered growth. Recent breakthroughs in blocking one of these mechanisms – the so called ‘immune checkpoints’ – put cancer immunotherapy back in the spotlights. Although promising, clinical benefits of these checkpoint inhibitors as single treatment has been limited to a subset of patients and goes along with unwanted systemic autoimmune toxicity. I hypostasized, that attacking the tumour microenvironment from multiple immunological angles simultaneously by local, conditional, and multimodal immunomodulation will greatly improve success of cancer immunotherapy and patient wellbeing. To achieve this, we developed a highly defined synergistic chemistry-based molecular therapeutic toolbox to specifically attack cancer, acting on effector T cells, macrophages as well as tumour cells simultaneously. In this highly multidisciplinary endeavour we (i) generated novel multifunctional dendritic cell targeted anti-cancer vaccines to ‘educate’ the patient’s immune system to recognise the tumour, (ii) we initiated the development of conditional, targeted immune checkpoint inhibitors to release the immunosuppressive break specifically within the tumour microenvironment and (iii) we generated chemical tools to locally eliminate the tumour-associated macrophages to tear down a major immunosuppressive barrier. We developed and utilized the novel ModimAb technology to obtain functionalized antibodies and antibody fragments. These individual therapeutic tools will allow me and my research team to explore uncharted tumour immunological territories in vitro as well as in vivo, greatly advancing the field of cancer immunotherapy. But above all, together they will form a highly dedicated symbiotic immunotherapeutic regime which will be extremely effective with reduced systemic side effects, dramatically improving patient care.