Lavenders are not particularly long lived plants, so could be that. Have you tried gently scraping, with a fingernail, some of the stalk covering to see if it looks green underneath? Otherwise, did you prune it back into old wood which some don't like - mine tend to survive me being brutal, but not all do. Someone else will be able to make more suggestions I expect.

welcome to GoY N/E

Does it still have its leaves? Scratch a bit of the bark off with your thumb nail. If it is green below then it is alive. if it is brown it is dead. Hope this helps.
Was it English or French lavender? English is hardier and usually survives for several years.
The French one is softer and is frost tender.

Mine too. I'm not sure what to do with mine either. It looks dead on the bottom yet green on top. I thought it was evergreen. When I can't stand it anymore - out it comes.

they are evergreen but as it grows the older woody stems loose their leaves. the sad thing is they don't like being cut back hard. ideally you trim them after flowering and avoid cutting back into new wood.
When you trim back use some of the bits as cuttings to keep yourself in plants. they need frost protection as cuttings I've found over the years.
The French lavenders [bunny ear lavenders as my girls called the flowers] are much more prone to the frost.

Unfortunately, I just can't meet the conditions this plant needs to thrive. Even my parsley can handle a lite frost. My lavender is done.