Q.Did it die? Is it possible for regrowth?
At the beginning of the winter I left my tomato tree outside for the 3 days. I had to cut the vines and cut the leaves because it was getting brown and it looked like it was dying. Now the stems look like hard wood. Did it die ,is it possible for it to regrow. It’s a cherry tomato tree.

Certified GKH Gardening Expert
Tomato plants do die back in the winter, but if you've kept it potted indoors, you could possibly see it sprouting back when spring approaches. Make sure to remove the hardened stems and dead leaves. If the roots have not survived the winter, the plant will not regrow.
This article may help with your question:
https://www.gardeningknowhow.com/plant-problems/environmental/how-to-tell-if-a-plant-is-dead-and-how-to-recover-an-almost-dead-plant.htm