Crystal Dynamics are still working on Marvel's Avengers but the latest update was meant to be improving experience on PC rather than adding more story about Hawkeye.
Marvel's Avengers kicked off with many performance issues, including the stability problems that caused random crashes for the players. Crystal Dynamics certainly had a lot to deal with after the release and the latest patch is one of the latent fixes that should've been there in the first place.
It's focused on dealing with stability problems on PC and it should now behave a bit better, on top of having better performance.
Depending on your rig's GPU, the game will automatically assign the graphics settings. For example, resolution will be set depending on your hardware, resolution scaling crash with DEVICE_HUNG error is not supposed to appear anymore.
Furthermore, Nvidia GPUs will get DLSS enabled by default and the game will be aiming for 60 FPS overall. Keep in mind that this may not be possible if your hardware is outdated.
Nvidia GPU users will be automatically asked to update drivers to 461.09 which is essential to smoothing the game experience. That said, there appear to be some issues with CPU usage still but it appears to be a minority of users, for now.
When the small remainder of the community goes through the content in a smoother fashion, they will eventually get to play Hawkeye.
Kate Bishop was introduced already but the original Hawkeye, Clint Barton, is still to make an appearance. He will be featured in a Showcase that will happen on February 16, 2021.