The family of myeloid-derived suppressor cells (MDSCs) includes a heterogeneous group of partially immature cells belonging to the myeloid lineage with potent immunosuppressive functions. They might be increased in the peripheral blood of cancer patients and in the microenvironment of cancer lesions, where they act in suppressing adaptive and innate immune cells, promoting tumor progression, and facilitating resistance to therapy. Several-albeit still limited-studies have shown higher levels of MDSCs in elderly cancer patients, correlating with poorer outcomes and a reduced response to immunotherapies. Thus, MDSCs may serve as biomarkers for prognosis or therapy response in this population, and MDSC-targeting therapies aimed at reducing their number or function may enhance the effectiveness of immunotherapies in older adults. Additionally, a better understanding of MDSCs may help to overcome some age-related barriers in cancer treatments.