Oddly enough, everyone in Wales is hoping for a tie in the USA-Iran game, they are out of the World Cup for sure if either side wins as they will only have four points if they can beat England today, whereas the potential winner of USA-Iran would have either five (USA) or six (Iran) points.
If Wales can win and there’s a tie in this game, then Iran and Wales both have four points, the USA are eliminated on three points. England win the group on five points. But Wales have a better goal differential than Iran already, and since this scenario requires them to win, that will improve further, while Iran’s tie would leave them on the same inferior goal differential. So that is the only way in for Wales.