Q.Rhubarb
Why did my rhubarb not come up this year?

Was this a new planting?
It is recommended to not harvest from the first season, to feed the plant.
Also the plant may need some winter protection. Covering the plant with leaf mulch, but not the crown can help.
Though Rhubarb is hardy once established, it can die from root rot.
I have also heard of rodents eating the roots over the winter months.
https://www.gardeningknowhow.com/edible/vegetables/rhubarb/grow-rhubarb.htm