After the arduous course of treatment is completed, lymphoma patients enter the relatively “easy” follow-up period. Some patients are very careful during the treatment period and cooperate well with medical and nursing care, but after entering the follow-up period, they start to be sloppy and casual, thinking that since the medication of their disease has been completed, the follow-up is just a formal review. In fact, as a malignant tumor, lymphoma also has the most terrible side of malignant tumors – recurrence. Therefore, temporary remission is not the end of victory. Follow-up after treatment is completed is essential for early detection of disease recurrence and improvement of survival rate. The vast majority of relapses in aggressive lymphoma occur within 5 years of the end of treatment, and the closer the time to the end of treatment, the greater the risk of relapse. The absence of relapse at 5 years is often considered a “clinical cure”, which shows how important the first 5 years of follow-up is. Some patients have the misconception that if lymphoma is relapsed, there is no hope and no need for further treatment, so it is useless to review and follow up. In fact, if recurrence of lymphoma is detected early and second-line chemotherapy and/or local radiotherapy is given actively, and if the patient is qualified, such measures as autologous stem cell transplantation can be considered to enhance consolidation, a significant number of patients can still be clinically cured again after such comprehensive treatment. Since follow-up after lymphoma treatment is so important, when should it be done? What should be taken into account during the follow-up? The recommended principle is: check regularly if you are not uncomfortable, and check whenever you are uncomfortable. The meaning of this statement is: when the patient does not have any discomfort, the recommended follow-up is once every 3 months in the first and second year after the treatment, and once every 6 months in the third to fifth year. However, if the patient has uncomfortable symptoms at the onset of the disease, such as fever, night sweats, unexplained weight loss, or masses on the body surface, or symptoms of organ involvement, etc., the patient may not be bound by the above time limit and should return to the hospital for follow-up as soon as possible to avoid missing clues of early relapse. The items of follow-up examination will be arranged by the hematologist according to the patient’s condition, including detailed medical history and physical examination; routine blood tests, biochemical (e.g. liver and kidney function, beta-2 microglobulin, LDH), immunological (e.g. lymphocyte subsets) and other laboratory tests; and electrocardiogram, tumor imaging and other tests. It is worth pointing out that the status of PET-CT in lymphoma follow-up has been fully reflected in recent years, and as one of the most sensitive examinations for tracking early lymphoma recurrence, more and more publications and guidelines recommend PET-CT as an important examination item for lymphoma follow-up instead of conventional imaging examinations such as chest X-ray and abdominal ultrasound. Finally, it should be pointed out that regardless of the results of the review, one should maintain a positive and optimistic attitude to overcome the common enemy of lymphoma together with family and medical staff.