TNFRSF8 and primary cutaneous T-cell non-Hodgkin lymphoma: This review aims to shed light on the critical importance of CD30, from its emergence in the cell to its position in diagnosing various diseases, including Hodgkin lymphoma, where it is expressed on Hodgkin and Reed–Sternberg cells, as well as embryonal carcinoma, anaplastic large cell lymphoma (ALCL), and cutaneous T-cell lymphoma (CTCL).