Stem cell therapy for Amyotrophic Lateral Sclerosis (ALS) faces several key challenges. One major obstacle is ensuring the survival and integration of transplanted stem cells in the patient's nervous system. Another issue is controlling the immune response to prevent rejection of the stem cells. Additionally, there is the difficulty of directing the stem cells to become the specific types of neurons that are lost in ALS. There are also concerns about the long-term safety and potential side effects of such treatments. Finally, more research is needed to understand the best methods and timing for administering stem cell therapy to achieve the most benefit for ALS patients.