PDCD1 and Lymphadenopathy: Before PD-1 inhibitors, all patients exhibited typical signs of CAEBV, including fever (13/16), lymphadenopathy (5/16), splenomegaly (9/16), hepatomegaly (4/16), cytopenia (8/16), abnormal liver function (8/16), and elevated serum ferritin levels (8/16).