Dear Manisha,What do you means by "lung cancer model"?
Is it a primary or a secondary (metastatic) tumor model?
If you search for a primary lung tumor model, as said by Dmitry, the LLC model is a good one. But it should be orthotopically grafted into the lungs and not subcutaneoulsy. Lung tumors in the "skin" are rather rare and the tumor microenvironment in the skin and in the lung is not at all the same. So, your immunotherapy approach can display distinct results whether a same tumor is implanted s.c. versus orthotopically.
If you are searching for secondary "metastatic" lung model, as said by Rodrigo, The B16F10 and the 4T1 models are OK.
However, be aware that the B16F10 "lung" model is a "pseudometastatic" and not an actual metastatic model because you must inject the B16F10 cells into the tail vein of the mice to have "lung tumors". You can use temozolomide as a positive chemotherapy control (see the attached article).
The 4T1 model represents an actual secondary (metastatic) lung cancer model because it arrises from orthotopic grafting of the 4T1 cells.