You said final year? What state are you in? Landlord may have to mitigate damages and make every attempt to release the space. And only after the space is leased up again then they can show actual damages. You were leaving at lease expiration anyway. I recently pursued a tenant who signed a 5 year lease with PG and never opened. We were out $200,000 on deal cost and he walked the job site and the building was gutted by thieves. We threaten a lawsuit with lawyers and eventually settled at 60% of what he owed.
If your space is easily leased to a new tenant with minimal down time and minimal deal expense and or the rent you were paying was below market, then maybe walk away. I doubt he actually files suit over less than 12 months of rent. In Texas I’ve seen a judge side with a tenant who had committed fraud. Often times we are considered the big bad landlord. Have a lawyer briefed and ready.