If you are at the forefront of a campaign or other activity, you have a leading and influential position in it.
They have been at the forefront of the campaign for political change.
他们一直处于政治变革运动的前沿。
If something is at the forefront of people's minds or attention, they think about it a lot because it is particularly important to them.
The pension issue was not at the forefront of his mind in the spring of 1985.
养老金问题在1985年春不是他思考的重心。