The original invention is still Edison’s. Latimer improvised it.
According to the history, Latimer made the first carbon filament and air evacuated bulb; Edison just improved on it. So, it seems Latimer was first with the concept. Edison was a charlatan in that he stole lots of Tesla’s idea’s and while Tesla was working for him didn’t pay him his salary saying it was an American joke to hire someone and not pay them.