This is a paid asset, but now you can download Futuristic Soldiers Pack Free.
Detail this asset from Unity Store: Original Link
Futuristic Soldiers Pack v1.0
Futuristic Soldier`s Pack is a realistic high-quality characters for your project. Pack contains: Futuristic Soldier Pack and Futuristic female soldier pack. There is a set of futuristic clothes and armor, and PBR materials for customization. The pack includes 26 body parts and 33 assembled models. Assembled character contains 30 thousand polygons on average, textures have a size of 4096 * 4096 and 2048 * 2048. Packaging has 107 quality BPR (metalness workflow) materials for customization. Skinned model and MotionBuilder/Unity Mecanim compatible skeleton.