Your description is a little confusing.
Do you have a cable box or do you get over-the-air TV signals using an antenna?
If you use a cable box, it may be simpler to connect the cable box and all your other devices to your AVR. Use a single HDMI cable to send video to the TV.
If you get OTA programming, then you do need an audio connection coming back from the TV to the AVR, using either a digital audio cable or Audio-Return-Channel over HDMI. Both TV and AVR need to support ARC in order for the latter to work.
Note that most TVs provide 5.1 surround-sound back to the AVR only for over-the-air broadcast stations, not for other input devices plugged into the TV. They only pass through stereo from directly connected devices. Carefully read your TV's manual to find out if ARC and multichannel audio are available.