With the synergistic advancement of micro/nano-fabrication technologies and intelligent control systems, medical microrobots are progressively overcoming the dual limitations of operational precision and invasiveness inherent in traditional diagnostic and therapeutic techniques, thereby providing innovative tools for precision medicine in critical diseases. However, current research predominantly focuses on artificially synthesized materials, whose complex fabrication processes and inherent immunogenicity risks not only lead to rapid clearance by the host immune system but also restrict their long-term therapeutic applications in deep tissues. The in situ construction of medical microrobots based on natural biological cells, achieved through precise modulation of their behaviors via external fields, may offer a transformative solution to resolve these challenges. This review systematically summarizes the design strategies of seven representative cell-based microrobots, including chemotactic bacteria, photosynthetic microalgae, autonomous contractile cardiomyocytes, red blood cells, platelets, macrophages, and neutrophils, with a focus on their recent advancements in drug delivery, minimally invasive surgery, and immunotherapy. Furthermore, this work critically analyzes the current challenges while outlining future research directions and clinical translation prospects.