We demonstrated cancer cell death based on the following: (1) cell death triggered by HA-CQDs through ferroptosis-based CD44-mediated endocytosis, (2) ferroptosis induction by HA-CQDs, marked by the assessment of ROS, depletion of GSH, downregulation of SLC7A11, downregulation of GPX4, and upregulation of lipid peroxidation. The gene discussed is CD44; the disease is cancer.