PDCD1 and melanoma: This study also revealed a significant shift in the type of systemic therapy used for the treatment of stage III and IV melanoma patients above 65 years: from 2008 to 2010 the standard first-line systemic treatment was chemotherapy or cytokines, while by 2015 to 2019 the majority of patients received PD-1 inhibitors alone or in combination with ipilimumab.