Cell therapies involve the use of living cells to treat or prevent disease. Cells are removed from the patient's body, then optimized in some manner before they're infused back into the patient. The medical community has relied on bone marrow stem cells as a method to treat cancer since the 1950s. Today, we live in the era of “ex vivo gene therapy.“ Contemporary cell therapies, like CAR-T, include the additional step of inserting a synthetic gene into transplanted cells. Once genetically re-engineered, the cells are introduced into the body to track down and kill cancer cells. Join Biotech Primer (biotechprimer.com) for our 90-minute Cell Therapy Primer talk. This introductory review of the cell therapy sector is intended for a broad audience.