MacBook Pro Touch Bar frozen

Symptoms

If the Touch Bar on your Mac is unresponsive or delayed when pressed
If your Touch Bar is blank with no video

Solutions

Soft Checks

Restart your Mac. Wait till the unit is powered back on before testing the Touch Bar again.
Check for any damage to LCD of Touch Bar. Sometimes any cracks or damage to Touch Bar will be small, and possibly hard to see. Shine a light over it to check for any small cracks or breaks.

Refresh Touch Bar from Activity Monitor

Open Activity Monitor from Applications > Utilities or search for it in Spotlight
Click the search bar and type "TouchBarServer"
Force quit this process. This should refresh your Touch Bar by going blank and returning to its default view.

Reset NVRAM

NVRAM (nonvolatile random-access memory) is a small amount of memory that your Mac uses to store certain settings and access them quickly. PRAM (Parameter RAM) stores similar information, and the steps for resetting NVRAM and PRAM are the same.

A step by step guide can be found here: TS1001 - Reset NVRAM

Reset SMC

The SMC (System Management Controller) is responsible for these and other low-level functions on Intel-based Mac computers:

Responding to presses of the power button
Responding to the display lid opening and closing on Mac notebooks
Battery management
Thermal management
Ambient light sensing
Keyboard backlighting

A step by step guide can be found here: TS1000 - Reset SMC

Advanced (Not suggested for new users)

Open Terminal from Spotlight, or Applications > Utilities
Type sudo pkill TouchBarServer and hit Return
This should force quit the Touch Bar
If this command still hasn't resolved the issue, attempt killall ControlStrip and hit Return