Liquid biopsies that detect cancer cells or DNA in blood are improving cancer diagnostics. The human microbiome may also influence cancer immunotherapies involving gut microbes. Patient-specific testing helps researchers determine the best treatment for each individual. Single-cell profiling can provide more detailed information about tumor heterogeneity and rare cell populations. Nanotechnology is being used to more precisely deliver cancer therapies. Stakeholders are working to improve cancer care through payment reform, eliminating ineffective treatments, and helping doctors and patients avoid inappropriate care.