There are few who would argue against a good walk. And any old walk will do. But if you want to walk mindfully, then Thich Nhat Hanh has a book that will help you do it. Quartz has a run down on it here: Zen master Thich Nhat Hanh explains how to walk more mindfully.
I think it could be great for people who have a hard time being mindful because they always need to be on the go. And for people who want to have more mindfulness in their life, it is also great. Read the article/book and improve your walks and your mind.