Updates "pending"
My app updates say pending on my Mac but they don't actually update. I'm on Mojave on a 2019 Air. I've made sure all OS updates are done and rebooted the computer. I'm waiting on Keynote, Pages and 3 others.
MacBook
I have had this happen before. Just give it some time to start downloading, there could be too much traffic on your internet connection at the moment. If that doesn't work, try again later.