In the past I was able to cast to Chromecast from my MacBook. But there's a lot of indications that this service may have been discontinued. For example, the Cast extension on Chrome has been discontinued. Is there still a way to cast to Chromecast from your MacBook? I find it perplexing that they discontinued this service since it was such a useful feature.
Fortunately, I am now able to cast on my computer. The trick is to set up Chromecast on your phone/tablet, as currently it cannot be setup from a computer. These days, Google Chrome has a cast option built-in, which can be accessed if you click the button with three vertical dots on the top right of Chrome. So there is no longer any need to download the Cast extension, as Chrome ships with it.