The neuromuscular system sounds a lot more confusing than it really is. Your muscular system is well, your muscles, and your nervous system is simply the nerves that communicate messages from your brain to other parts of the body (such as your muscles).
So your neuromuscular system is your muscles and the nerves that connect to these muscles. Thus, all training is technically neuromuscular training because it involves the contractile machinery of the muscles and the neurons communicating with the muscles from the nervous system.
When we talk about adaptations, we can have muscular adaptations that are specific to muscles themselves, like improving muscle size and improving/changing fiber types. This is also partly why a concept frequently talked in bodybuilding called the mind to muscle connection is so important!
We can also have neural adaptations like conduction velocity and central drive. But, even though these adaptations are localized, the nervous and muscular system always work together. So while training might theoretically focus on specific areas, more muscle size, or speed of neural transmission, they never truly work in isolation.