CEACAM5 and cancer: In this study, we developed a nanozyme‐linked immunosorbent surface plasmon resonance (nano‐ELISPR) biosensor integrating the low‐cost nano cup sensor with Au@Pt NFs, for ultrasensitive, rapid, and portable testing of three cancer biomarkers serum levels, including AFP, carcinoembryonic antigen (CEA), and carbohydrate antigen 125 (CA125).