Well, the question is a bit unspecific. It depends on what you wanna do and which cells/models you wanna use. There are genetic mouse models of metastasizing lung cancers (for an example see here: https://www.nature.com/articles/1210493). The more commonly used method are transpantations. Here again, it depends on what you wanna do or see. Most commonly used are tail vein, or intracardial injections, with the latter having a higher prevalence for brain metastases than tail vein injections. The mice to use then depend on if you want to use murine or human lung cancer cell lines. In case of lung cancer metastasis, one can also use orthotopic or subcutaneous implantation models to see if the primary tumor will metastasize. A general overview about mouse models of metastasis you can find here for exaple:

doi:10.1242/dmm.030403

Thank you very much @Sascha Seidel.I want to study human lung cancer cell lines (mainly A549) and want to see how primary tumor will metastasize before and after treatment with anti-cancer drugs.

Soumyajit Biswas, in that case i'd recommend a subcutaneous transplantation of the A549 cells in immunodeficient mice. We usually use the outbred NMRI nu, which works well with this cell line in our case, but you can choose different immunodeficient mouse strains if you want. With this model we usually see metastasis formationinly in the lung and/or liver and it will allow you to perform your treatment to see if the metastatic spread is altered depending on your anti-cancer treatment. If you have luciferase expressing cells, you can follow metastatic spread with in vivo bioluminescence measuremts. In case the primary tumor exceeds the endpoint citeria and no metastases are detectable, you can also resect the primary tumor easily to follow up metastasis formation, even if in your case this would mean the end of treatment for your primary tumor.

Thank you @Sascha Seidel for your valuable suggestions.