CD4 and Hodgkins lymphoma: The malignant Hodgkin and Reed-Sternberg (HRS) cells typically account for only about 1% of cells in the tumor tissue, and they are embedded in an inflammatory infiltrate of many different immune cells, including mainly CD4+ helper and regulatory T cells, and varying proportions of B lymphocytes, cytotoxic T cells, NK cells, granulocytes, and macrophages.2 HRS cells show multiple immune evasion strategies,3 but treatment of HL patients with ICIs such as nivolumab has demonstrated excellent clinical responses.4 However, some patients fail to respond to ICI therapy or develop resistance.