Carsten Krieg, Ph.D., assistant professor in the Department of Microbiology and Immunology at the Medical University of South Carolina, discusses how “Instagrams of the immune system,” captured by a new technology known as high-dimensional single-cell mass cytometry, and a novel bioinformatics pipeline, made it possible to identify biomarkers of response to immunotherapy in patients with melanoma. The findings are reported in the February 2018 issue of Nature Medicine.