1. Evaluate lymphocyte function and overall assess the immune function status of the body
2. Monitor changes in immune function in tumor patients and evaluate prognosis
3. Monitor the therapeutic effect of PD-1/PD-L1 monoclonal antibodies and evaluate the occurrence of immune related adverse events
4. Assessing the progression and stage of infection can aid in determining the body's capacity to eliminate pathogens and the extent of damage to the body
