I wouldn't say "strictly" land warfare, although predominantly so. Many insurgents have some naval element, e.g. arms trafficking for the Viet Cong and FMLN, and water borne raids in the Niger Delta. I can't think of any with an air component, but it's not out of the question. Plus, there is the tricky question of the informational battlespace. That is a major one for insurgents but is not, strictly speaking, land warfare.
I would not consider the French resistance insurgency. Certainly it was guerrilla war. But I don't think the resistance ever though it could attain its strategic objectives on its own (although when I visited the French military museum in Paris, I learned how the the French resistance decisively defeated the Germans while a few Brits, Canadians, and Americans sort of lingered in the background).
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