Cordyceps (Cordyceps militaris) contains cordycepin, a compound that helped immune cells move into melanoma tumors and shrink tumor volume in mice. At 20 µM, cordycepin increased immune-cell cleanup of tumor material, boosted tumor-targeting movement, and raised key immune signals linked to cancer-cell clearance. The strongest result came when cordycepin-primed immune cells were injected directly into tumors, reducing both tumor size and weight while increasing cancer-cell death markers.