Tennis shoes and sneakers are pretty similar to each other but they are different.
Sneakers are basically simple shoes that are made with rubber soles and a canvas topping.
Tennis shoes are sneakers made with the same thing basically but are made much more durable and harder to hold up to playing tennis.
That is why shoes are called Tennis shoes so if you're playing Tennis you really want to buy Tennis shoes and if you're just running or walking then regular sneakers or regular shoes would be okay.
But you can run in Tennis shoes or walk in Tennis shoes as well.
I always called them Tennis shoes when I was a kid even though I never played tennis.
I guess the name just stuck with me and it's what my parents called them as well.