Need help with a gift

I'm looking to gift a model kit to a good friend of mine. Problem is I know nothing about this hobby, and I absolutely don't want to let on the surprise as this is for his birthday. What I can tell you is that he has a lot of experience with Lego building but I didn't wanna gift him a set of Legos as that would be pretty basic. His main interests are WWII, tanks, and middle eastern conflicts. Can you maybe recommend some sets that you think he would like, and equipment I should get him to go along with as I'm not sure what he already has and does not have at home. Thanks so much in advance! Budget isn't that much of an issue.