It only shows up for people using a mouse. If you use your fingers, it will never show up.
It cannot be turned off. People with a mouse complained that there was no (easy) way (for them) to close or minimize an app, so they got what they wanted. But again, it will never show up if you use your fingers, so it's only there for traditional desktop (mouse and keyboard) users.
If you aren't using a touch screen, Microsoft never thought you'd be using the tablet apps (tablet mode) anyway. Why are you using Chrome like that, when you could just use it on the desktop?