In CAR-T cell therapy, one of the main challenges to obtaining a consistent, reproducible manufacturing process and therapeutic product is the variation of the cellular starting material. However, one should not overlook the importance of raw materials. Proper selection and control of raw materials and their suppliers/manufacturers are critical moving forward during clinical development. It will impact process and product quality, safety, consistency, but also support continuous manufacturing and cost of goods control. In this opinion piece, we describe based on our experience a practical and effective risk-based tool to prioritize effort towards raw materials during clinical development. This approach should help identifying weaknesses and establish an action plan to prepare for commercial raw material readiness.