DISEASE CHARACTERISTICS: Histologically confirmed metastatic renal cell cancer or melanoma Measurable disease

PATIENT CHARACTERISTICS: Age: 16 and over Performance status: ECOG 0-1 Life expectancy: More than 3 months Hematopoietic: WBC at least 3,000/mm3 Platelet count at least 90,000/mm3 No coagulation disorders Hepatic: Bilirubin no greater than 1.6 mg/dL AST and ALT less than 2.5 times normal Hepatitis B surface antigen negative Renal: Creatinine no greater than 2.0 mg/dL Cardiovascular: No major active medical illness of the cardiovascular system (e.g., cardiac ischemia, myocardial infarction, or cardiac arrhythmia) Pulmonary: No major active medical illness of the respiratory system (e.g., obstructive or restrictive pulmonary disease) Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No active systemic infections No history of autoimmune disorders HIV negative

PRIOR CONCURRENT THERAPY: Biologic therapy: At least 3 weeks since prior biologic therapy No prior systemic flt3 ligand or CD40-ligand Chemotherapy: At least 3 weeks since prior chemotherapy Endocrine therapy: At least 3 weeks since prior endocrine therapy No concurrent systemic steroids Radiotherapy: Prior localized radiotherapy for renal cell cancer or melanoma allowed Surgery: Prior surgery for renal cell cancer or melanoma allowed