Finally, although our work has highlighted the importance of target endosomal models in understanding transfection trends, larger benchmarks with more extensive sets of LNP formulations are needed. Also comparing against in vitro experimental fusion trends, and not only with in vivo protein expression , may help to isolate the impact of fusion from other factors affecting RNA delivery efficiency, such as LNP structure and the interaction strength of ILs with nucleic acids. Detailed lipidomics studies of endosomal membrane composition in different cell types could also improve the accuracy of observed trends and aid in developing cell-specific LNP formulations, which is a significant goal in the field, especially for promising cancer vaccines .