The most common consequence of low immune surveillance function is cancer formation. Due to the influence of external and internal environment, the genome of human cells is always undergoing abnormalities such as breakage, mutation and fusion, and some genetic abnormalities may lead to the activation of oncogenes in cells causing cancer. Once cancerous cells are found, a series of immune reactions will be activated to remove them and prevent them from growing in the body and eventually forming cancerous tissues. If the immune surveillance function is low and the ability of error correction is reduced, cancerous cells can easily escape from immune surveillance and grow into cancer. In addition, low immunosurveillance function can also lead to increased risk of infection because the immune system is also responsible for monitoring and fighting against the invasion of bacteria, viruses and other microorganisms from outside the body.