Chronic lymphocytic leukemia, or CLL for short, is a neoplastic disease with slow progression and low malignancy, manifested by the accumulation of morphologically mature lymphocytes in the lymphoid tissue (including peripheral blood, bone marrow and lymph nodes, spleen, etc.), bone marrow and peripheral blood in the body, which can form masses or affect normal hematopoietic function. Therefore, although slow lymphoma is essentially a neoplastic disease, some patients have slow disease progression, some even carry the disease for life without any symptoms and do not affect survival, but some patients have faster progression and need immediate chemotherapy or even hematopoietic stem cell transplantation, while others have progressive disease that eventually requires treatment. Small lymphocytic lymphoma (abbreviated as SLL) refers to this type of neoplastic lymphocyte infiltration mainly in lymph nodes, spleen and other lymphoid tissues, mainly in the form of masses, without significant involvement of bone marrow and peripheral blood, while CLL mainly manifests as leukemia and can be accompanied by masses. The diagnosis of SLL is largely the same as that of CLL, except that the diagnosis of SLL depends mainly on lymph node pathology and immunohistochemical examination.