PDCD1 and lung carcinoma: Chen and co‐workers prepared CMNs overexpressing PD‐1 through genetic engineering of TC‐1P cells, and showed that PD‐1 overexpressed on the surface of CMNs were bound to PD‐L1 on the surface of lung cancer cells, exerting anticancer efficacy.[16] While genetic engineering is a favorable method to endow CMNs with additional features, various limitations remain – the process of genetic engineering is complex, labor intensive, and unpredictable, and not all cells can be easily genetically modified.