One of my least favourite features of Microsoft Teams is the tenant switching. If a customer has added me to a Team in their tenant, I have to switch to theirs and log in whenever I want to access or share something with them. If I am on a Teams call in my company’s Teams tenant, I have to end the call to access something from another tenant.
Shared Channels is a feature being released by Microsoft this year (2022) that will help solve that issue. More info here. But for now, I like to run multiple instances of Teams to access another tenant while logged into my own.
What I mean by multiple instances is the ability to have more than one Teams window open at one time on my computer.
To do this, open up any browser and log in to Teams online with the exact login details I use for the desktop app.
Then click on the three dots and choose more tools > create a shortcut.
A box will appear asking to create a shortcut. Name the window whatever you want, and make sure you select open as a window.

Once I do that, it will open a Teams windows so now I have 2 on my desktop:

I love having 2 instances of Teams, even if I don’t need to login to another tenant, I can use one for viewing a specific channel, the other for chat or calendar.