Complex sentence: The commercial opens with a dystopic, industrial setting in blue and gray tones, showing a line of people (of ambiguous gender) marching in unison through a long tunnel monitored by a string of telescreens.
Split into simpler sentences: The commercial opens with a dystopic, industrial setting in blue and gray tones, showing a line of people (of ambiguous gender) marching in unison. They are moving through a long tunnel monitored by a string of telescreens.