I saw a video on this recently. I think it was Wendover.
Though card counting is still possible many casinos have made it very difficult. Most methods require the counter knowing what is left in the deck.
Two methods are just using 3-5 decks and reshuffling the deck after eatch hand. This apprently stops all but the most insanely talented card counters. Some go further using a machine to shuffle the deck in a way players can’t see.
Though it also mentions some players think this cheating for the house so it might not be done at every casino