Tumors are spatially organized ecosystems that are comprised of distinct cell types, each of which can assume a variety of phenotypes defined by coexpression of multiple proteins. However, knowledge of the composition, phenotype, organization, and interactions between tumor cells, immune cells and stroma is limited. Our lab applies multiplexed imaging to study the interplay between different cells in the tumor in order to identify design principles of tumor organization that may be therapeutically relevant. Current areas of focus include melanoma response to immunotherapy, intra-tumor heterogeneity and lymph node metastasis.