The American League and National League Championship Series are set to begin on Friday, and if you're a baseball fan, there are a few ways of watching on Apple devices instead of expensive tickets or trundling over to a local sports bar.
All of them, though, require some form of live TV service. Specifically you need a package with FS1, Fox, and/or TBS -- that includes most U.S. cable and satellite providers. Many if not all of them will let you authenticate with Fox Sports Go and Watch TBS, both of which support the iPhone, iPad, and Apple TV. Note that you'll want Fox specifically for the World Series.
You can also go through MLB.tv, but that still requires authenticating a provider on top of a $24.99 postseason fee, so only diehards need apply.
If you're a cord-cutter, you're in luck. Several internet TV streamers with iOS and tvOS apps are offering the needed channels, including Sling TV, PlayStation Vue, Hulu, DirecTV Now, and YouTube TV.
Sling's Blue package is your best bet if you're planning to pay -- it includes FS1, Fox, and TBS for $25 per month.