Core Viewpoint - Cancer metastasis and recurrence remain the leading causes of cancer-related deaths, particularly in the lungs, necessitating new treatment strategies to improve outcomes for patients with lung metastases [2][5]. Group 1: CAR-T and CAR-M Therapies - CAR-T cell therapy has shown significant success in treating hematological malignancies, prompting ongoing trials for its application in solid tumors, despite challenges such as high cytotoxicity and insufficient tumor infiltration [2][3]. - CAR-M therapy is emerging as a promising candidate for cancer treatment due to its superior tumor infiltration and antigen-specific phagocytic capabilities, as well as its role as a specialized antigen-presenting cell [5]. Group 2: Research Findings - The recent study by the team at Sun Yat-sen University developed an inhalable engineered small extracellular vesicle (sEV) that delivers mRNA to generate CAR macrophages (CAR-M) in situ, effectively mitigating lung metastasis and preventing recurrence [3][11]. - Experimental results in mouse models demonstrated that inhaled CAR mRNA @aCD206 sEV accumulates in lung tissue, specifically delivering CAR mRNA to macrophages, thereby promoting the in situ generation of CAR-M cells and effectively inhibiting tumor growth while stimulating long-term memory immunity to prevent recurrence [9][11]. Group 3: Challenges and Innovations - Despite the potential of CAR-M therapy, challenges such as complex manufacturing processes and accumulation in the liver post-intravenous administration limit its broader application [6]. - The engineered sEV delivery platform developed in this research offers a promising new immunotherapy strategy to effectively combat lung metastasis and recurrence by selectively delivering CAR mRNA to macrophages in lung tissue [11].