I wasn't sure these were all in the last five years, but when I checked the dates, they mostly are:
- Microsoft: Visual Studio Code (2015), acquired GitHub - getting deep into dev tools outside the Windows market
- Apple: Apple Watch (2015) - wearable health tech
- Amazon: original TV and movies, grocery delivery, acquired Whole Foods (2017)
- Facebook: acquired Instagram (2012) and WhatsApp (2014), Oculus VR
- Netflix: original feature films (e.g. Roma, 2018)
You may not consider all those to be new markets; e.g. Netflix is still pretty much just doing streaming video as far as I'm aware. But it was still seen as a big deal when they started doing original TV shows (House of Cards) and then "proper" original movies.
Edit to add: Google: AI tools & infrastructure? I don't know enough to judge if they're making a big impact there.