However, none of this functionality is built in. You'll need to have an Alexa or Google Assistant-powered smart speaker in order to issue commands to your Samsung TV. As we discovered when testing out the feature in person during CES 2019, Bixby is still the only assistant that's integrated, letting you issue voice searches through the remote control.
But if you do have an Alexa or Google speaker, you can use it to change channels, turn the TV on/off, adjust the volume and switch between inputs. Testing it out at Samsung's CES event, we were able to channel switch by calling out, "Alexa, switch to ESPN".
Unlike support for Apple iTunes and AirPlay 2 - also just announced - Samsung isn't saying anything about pre-2019 TV models - hopefully this can be easily added with a software update.
There were rumors circulating ahead of CES that Samsung would announced Google Assistant integration with its TVs, but it was expected this would be baked in. Samsung obviously wants to give people a reason to still use Bixby, but it also knows that Alexa and the Google Assistant are extremely popular - and ignoring them altogether could be to its detriment in the long run.