These findings suggest that anti-PD-1 treatment affects the frequency of lymphocytes and their intracellular and surface HSP90 expression in r/r cHL lymphoma patients, however, further studies are required to assess the effect of anti-PD-1 treatment on HSP90 expression and localization in bone marrow and peripheral blood lymphocytes. The gene discussed is HSP90AA1; the disease is classic Hodgkin lymphoma.