PDCD1 and cancer: In melanoma, only few studies distinguish between the tumor core and the invasive margin.39 72 73 B cells have also gained a lot of interested in cancer research as they have been associated with favorable prognosis.76 Recently, particular B cell formations designated as tertiary lymphoid structures have been associated with response on anti-PD-1 and to a lesser extent anti-CTLA-4 immunotherapy.77 However, in this study, the density of B cells did neither in the invasive margin nor in the tumor correlate with response to ipilimumab.