While Husserl focused on cognition, Heidegger, Merleau-Ponty and Sartre were more interested in ‘being', or existence, and so are often referred to as existential phenomenologists.
The core concern for Heidegger was being; that is, being as a verb, the act of existing, rather than being as a noun.
For Heidegger, we are always already in the world, and so it makes no sense to ‘bracket’ the world as if it may not exist.
The emphasis on being-in-the-world is captured in Heidegger’s (1953) notion of Dasein → which translates as ‘being there’.
We understand existence only through existence, and understand the world only through existing in it. All of our knowing is founded on our being-in-the-world.
Heidegger → concept of ‘dwelling’.
We do not just ‘inhabit’ the world → we live in and through the world. He lets us questions about what it is to be human.
The key to Merleau-Ponty’s phenomenology is embodiment.
Your being-in-the-world is an embodied being, and your body is central to your consciousness, knowledge, understanding and intentionality.
You experience the world from and through your body.