Your smartphone is capable of doing a lot for you, and mirroring it on your TV might be another unique feature you can take advantage of. Although not every smartphone or TV has this capability, most do. 

If you are an Android, you can use Miracast.

Miracast is a standard for wireless connections from sending devices (such as laptops, tablets, or smartphones) to display receivers (such as TVs, monitors, or projectors), introduced in 2012 by the Wi-Fi Alliance. It can roughly be described as “HDMI over Wi-Fi“, replacing the cable from the device to the display.