The Safe Stop trial (NTR7502, EudraCT: 2018-001384-23) is a study in the Netherlands looking at early discontinuation of first line anti-PD-1 therapy (nivolumab or pembrolizumab) for advanced or metastatic melanoma patients who have achieved a confirmed CR (with an interval confirmatory imaging of at least 6 weeks after first documentation) or an ongoing PR (with an interval of 12 weeks after first documentation). The gene discussed is PDCD1; the disease is metastatic melanoma.