IMMUcan proposes an inclusive and integrated European immuno-oncology platform. IMMUcan will access high-quality human biological material (tissue, blood, stool and saliva) and clinical data from patients with colorectal, lung, head & neck, breast, gastric cancers and immune checkpoints inhibitors failures. We have assembled a strong consortium with ten expert clinical centers, access to large volumes of the required tumor types. IMMUcan will mobilize the majority of academic trials running or expected to start recruiting patients during the project period. A centralized workflow for samples, via a state-of-the-art biobank will increase reproducibility as all tissues will be processed and stored in a uniform way, following proofed SOPs. The project will perform in depth immunoprofiling with cutting edge technologies including CyTOFF, single cell RNA-seq, peptidogenomics or microbiome analysis. IMMUcan will analyze the data in order to understand the host/tumour interaction in the absence of treatment (naïve population) and with treatment (patients in follow-up) to identify potential predictive biomarker for response to immunotherapy, or develop rationale for combination therapies. IMMUcan will provide an IT platform and legal/ethical contractual framework where participants from both academia and industry can pursue their own independent investigations utilizing the IMMUcan data and effectively testing and improving the functioning and relevance of the database. A sustainability plan will be developed to ensure the collection of follow-up data and the accessibility of the data platform. The use of the data generating throughout this project, for future research, will be supported.