Gaming on Linux has certainly come a long way since I first tried it under Ubuntu years ago – so much so that I'm now playing games on Linux 90% of the time. For the other 10% of my time I'm dual booting back into Windows 10 if I absolutely have to.
First, we're going to need Lutris. Lutris is an open source gaming platform for Linux. At a lower level, it's a collection of curated scripts to install and run games that do not support Linux natively.
Thankfully Lutris is in the main repo under Arch Linux so installation is simple, for other distributions see their installation page.
sudo pacman -S lutris
DXVK is a Vulkan based implementation of Direct3D 10/11 that runs on Linux/Wine. This is required for many Windows-only games and Lutris will manage most of this for us, all we need to do is install Wine (staging) and some Vulkan dependencies.
sudo pacman -S wine-staging vulkan-icd-loader lib32-vulkan-icd-loader
Once these are installed, boot up Lutris and install Overwatch via the search box!