This article discusses the care process among three groups (primary care, radiology, and surgery) aiding a 57-year-old woman during her screening mammography and diagnosis of breast cancer. This is the first in a series of articles exploring principles and topics relevant to teams guiding clinicians involved in cancer care. The challenges demonstrated in this case illustrate how clinicians work within and between groups to deliver this first phase of cancer care. The case helps demonstrate the differences between groups and teams. Focusing on the patient and the overall process of care coordination can help move groups toward becoming teams who deliver better care by identifying and managing goals, roles, and interdependent care tasks. Care providers and researchers can use the case to consider their own work and essential aspects of teamwork needed to improve care, patient outcomes, and the evidence that supports each.