PDCD1 and cancer: To extrapolate these observations and their potential clinical investigation to patients, we next examined ISG scores in a melanoma cohort following PD‐1 treatment.[48] Although global ISGs expression and ISG scores of cancer cells (normalized by EPCAM) did not show differences between responders and non‐responders, ISG scores of immune cell populations (normalized by PTPRC) in responders were much lower than those in non‐responders (Figure 5D), confirming that prolonged ISGs in immune cell populations, especially in myeloid cells (Figure 5E), might be associated with ICB resistance.