Updated February 20, 2020:: Depreciated. There is now no difference between being in and out of combat now that we have a huge new innovation in the works.
There are a number of ways to keep track of initiative order / turn order in games. I’ve seen writing on clothes pins attached to a board game box, simply writing it down on a piece of paper, and probably the most common would be creating little paper or cardboard flags that fold over the GM screen:
Gambit will use the format shown in the picture above, but the flags will be pre-printed and ready to use.