RecruitingPhase 2ProcedureA Study of Pembrolizumab Plus Local Chemotherapy Using Isolated Limb Infusion (ILI) for Patients With Sarcoma in the Arm or LegThe purpose of this study is to find out whether giving the study drug pembrolizumab in combination with the chemotherapy drugs melphalan and dactinomycin, delivered directly to the affected arm or leg using a technique called isolated limb infusion (ILI), is a safe treatment that can delay the time before your disease gets worse (progresses).