Basements are where laminate either lasts for years or buckles in a single summer. The difference is moisture control.
We test the slab before we quote. If the basement has had standing water or shows white efflorescence on the walls, we tell you that straight, because no flooring will fix a water problem. If the slab is dry enough for the product, we lay 6-mil poly with taped seams, then a foam or cork underlayment on top.
Basement slabs often slope toward a floor drain. That slope is fine for water but bad for a floating floor. We level the area where the laminate will go so the planks sit flat and the joints do not flex.
We leave the full 1/4 to 3/8 inch expansion gap at foundation walls. Basement walls are cold in winter, and humidity near them swings more than upstairs. A dehumidifier set around 50 percent helps any below-grade floor. Waterproof laminate is our usual pick down here. See laminate over concrete installation for how we prep slabs.