This is a prospective, single-arm, open-label, early exploratory clinical study designed to evaluate the safety, tolerability, and efficacy of the DQ1001 cell product in patients with relapsed or refractory multiple myeloma. All participants will receive intravenous infusions of DQ1001. The study consists of two phases: dose escalation and dose expansion. Following identification of an optimal dose during the dose-escalation phase, the cohort receiving that dose will be expanded to include a total of 12 participants-including those enrolled during dose escalation-to further assess the safety, tolerability, and efficacy of DQ1001.