Concealed carry is still a thing in several states that haven't adopted Constitutional Carry laws yet. If you live in one of those states and have the desire to exercise your 2nd Amendment rights in concealed fashion, you must apply for a permit (you know, those nasty little things you have to get when the government steals your rights away, then sells them back to you) and be approved before you can tuck a gun in your waistband or a concealed carry holster.
Now, for some of us, concealed carry isn't a concern...I live in an Open Carry state and several of us do...lunch time around town looks like an old western just with newer guns...almost everybody has one on their hip or attached to the underside of the dash in the vehicle...which leaves very few of us concerned with concealed carry...we just don't have the need...there are so many open carry citizens you never have to worry about being the target of a bad guy.