Building further on the goal of engineering immunity, our second major area of research is the development of synthetic materials that enhance the safety and potency of cellular and molecular immunotherapies. We have focused recently on multiple coordinated strategies to enhance cancer immunotherapy, using approaches that are also broadly applicable to infectious disease. Examples include the development of nanoparticle-based drug delivery “backpacks” for T-cells that can be used to enhance adoptive T-cell therapy of cancer, and the use of lipid nanoparticles to anchor locally-administered immunotherapy agents within tumors, for enhanced safety and efficacy of potent immunomodulators. We discovered a powerful but simple technology for targeting immunotherapy agents to lymph nodes through “albumin hitchhiking”, and have used this molecular targeting strategy to enhance cancer vaccines and boost the activity of chimeric antigen receptor T cells in cancer. These novel nanomaterials may provide a new way to achieve for highly efficient delivery of drugs or diagnostic agents into cells for therapy or monitoring of cellular processes.