A soft 20 in Blackjack refers to a hand that includes an Ace counted as 11, combined with a 9 (Ace-9). This is a strong hand, and the basic strategy is generally to stand. The reason for this is that you already have a total of 20, which is a very strong hand that has a high chance of winning against most dealer hands.
Unlike a hard 20 (which could result from a hand like 10-10), a soft 20 is flexible because of the Ace, meaning you can't bust by taking another card. However, the best move is usually to stand because the odds of improving your hand (without going over 21) are low, and the dealer is more likely to bust or end up with a weaker hand.
In short, when you have a soft 20, you should always stand.
Unlike a hard 20 (which could result from a hand like 10-10), a soft 20 is flexible because of the Ace, meaning you can't bust by taking another card. However, the best move is usually to stand because the odds of improving your hand (without going over 21) are low, and the dealer is more likely to bust or end up with a weaker hand.
In short, when you have a soft 20, you should always stand.