Hey, this is a great question. The particular model you clicked on, is AT&T, however, if you are looking for an S7 Unlocked model, see here (https://www.bestbuy.com/site/samsung-galaxy-s7-4g-lte-with-32gb-memory-cell-phone-unlocked-black-onyx/5286503.p?skuId=5286503) .
As far as the warranty goes, all Samsung products have a 1-year Limited service warranty. ^Sarah