Despite immense progress in the surveillance of cancers, such as serum markers circulating tumor DNA, circulating tumor cells, carcinoembryonic antigen, non‐invasive examination ultrasound, computed tomography (CT), magnetic resonance imaging, positron emission tomography (PET) and PET/CT, and so forth, the number of cancer cases still has not decreased over the years. Here, CEACAM5 is linked to cancer.