When playing basketball, is it a foul to step on someone?

In most cases, it is not a foul.

Unless. .

He is perverted or has an obvious purpose

Just like when preparing to catch a ball or grab a basketball, if you deliberately step on someone at this time, making it impossible for them to interact normally and fairly. If the opponent fights for it, it must be a foul

But it is usually not discovered by the referee

(Everyone knows that the referee is looking at the ball and hands)