Recent studies showed that circulating immune cell signatures, such as CD4+ T cell TCR repertoire diversity, natural killer (NK) cell abundance, and newly identified CD3-CD68+CD4+GrB+ cell subset, correlating with therapeutic response to PD-1 blockade in classical Hodgkin’s lymphoma,20 inspiring us to assess peripheral blood biomarkers relating to treatment response. This evidence concerns the gene CD4 and Hodgkins lymphoma.