@htam9876,
Company has more than one meaning, it can mean a firm, a limited company, but more often it means not being on your own.
Company is often seen as a good thing as in the phrase ‘Two’s company, three’s a crowd,” meaning two people in love don’t want a third party getting in the way.
In short, “We’ve got company,” just means that you’ve been joined by one or more others. In a conflict situation it usually refers to the enemy.