Malignant melanoma is a highly lethal neoplasm, with 50% of patients succumbing to metastatic disease within five years of diagnosis. Recently, the important role of the immune system in modulating cancer progression has emerged, leading to the rapid development of cancer immunotherapies. However, biomarkers to guide therapy are lacking. This research will utilize a novel high-dimensional imaging technology (Multiplexed Ion Beam Imaging by Time of Flight) to study the tumor immune microenvironment in dozens of melanoma patients treated at Hadassah Medical Center. The goal is to generate predictive biomarkers, to guide patient-specific selection of therapies from a growing arsenal of cancer-immunotherapies.