in step
1. when you lift your feet off the ground and put them down again at the same time as other people:
The soldiers marched in step.

2. describes opinions, ideas or ways of living that are the same as those of other people:
Television companies need to keep in step with public opinion.

[TahlilGaran] Advanced Learner's Dictionary ▲

in step
adv. or adj. phr.
1. With the left or right foot stepping at the same time as another's or to the beat of music; in matching strides with another person or persons.
The long line of soldiers marched all in step: Left, right! Left, right!
Johnny marched behind the band in step to the music.
2. In agreement; abreast.
■ Often followed by "with".
Mary wanted to stay in step with her friends and have a doll too.
Antonym: OUT OF STEP.

[TahlilGaran] English Idioms Dictionary ▲