Severe systemic toxicity and poor targeting efficiency remain major limitations of traditional chemotherapy, emphasising the need for smarter drug delivery systems. Magnetic 2D transition-metal-based nanomaterials offer a promising approach, as they can be designed to combine high drug loading, precise targeting, and controlled release. The key material classes-transition metal dichalcogenides, transition metal carbides/nitrides, transition metal oxides, and metal-organic frameworks-share important physicochemical properties. These include high surface-to-volume ratios, tuneable functionalities, and efficient intracellular uptake. Incorporating magnetic nanoparticles into these 2D structures broadens their potential beyond drug delivery, through enabling multimodal therapeutic strategies such as hyperthermia induction, real-time imaging, and photothermal or photodynamic therapy. This review outlines the potential of magnetic 2D transition-metal-based nanomaterials for biomedical applications by evaluating their therapeutic performance and biological response. In parallel, it offers a critical analysis of how differences in physicochemical properties influence their potential for specific cancer treatment applications, highlighting the most promising uses of each in bionanomedicine.