Recent biomaterials like nanoparticles, graphene, and functional hydrogels are advancing tissue engineering and disease therapy through immunomodulation, tissue regeneration, and cancer therapy. This study explores the role of biomaterials in enhancing immune responses and promoting tissue regeneration. Implantable biomaterials offer innovative therapeutic effects in various disease situations. Understanding the interactions between biomaterials and host cells is crucial for creating therapeutic biomaterials that facilitate tissue integration and mitigate foreign body reactions. This study emphasizes how biomaterial properties, like size, shape, surface composition, and mechanical characteristics, influence immune cell responses, particularly macrophage polarization, which is crucial for minimizing inflammation and supporting tissue repair. The findings underscore the importance of tailored biomaterial design to mitigate foreign body reactions, improve biocompatibility, and ultimately enhance patient outcomes.