Same for me.

Computer Information:
Manufacturer: Unknown
Model: Unknown
Form Factor: Desktop
No Touch Input Detected

Processor Information:
CPU Vendor: GenuineIntel
CPU Brand: Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz
CPU Family: 0x6
CPU Model: 0x5e
CPU Stepping: 0x3
CPU Type: 0x0
Speed: 4200 Mhz
8 logical processors
4 physical processors
HyperThreading: Supported
FCMOV: Supported
SSE2: Supported
SSE3: Supported
SSSE3: Supported
SSE4a: Unsupported
SSE41: Supported
SSE42: Supported
AES: Supported
AVX: Supported
CMPXCHG16B: Supported
LAHF/SAHF: Supported
PrefetchW: Unsupported

Operating System Version:
Ubuntu 16.04.5 LTS (64 bit)
Kernel Name: Linux
Kernel Version: 4.4.0-139-generic
X Server Vendor: The X.Org Foundation
X Server Release: 11804000
X Window Manager: Compiz
Steam Runtime Version: steam-runtime-beta-release_2018-10-24

Video Card:
Driver: NVIDIA Corporation GeForce GTX 1070/PCIe/SSE2
Driver Version: 4.6.0 NVIDIA 396.54
OpenGL Version: 4.6
Desktop Color Depth: 24 bits per pixel
Monitor Refresh Rate: 59 Hz
VendorID: 0x10de
DeviceID: 0x1b81
Revision Not Detected
Number of Monitors: 2
Number of Logical Video Cards: 1
Primary Display Resolution: 2560 x 1440
Desktop Resolution: 3840 x 1440
Primary Display Size: 23.50" x 13.23" (26.97" diag)
59.7cm x 33.6cm (68.5cm diag)
Primary Bus: PCI Express 16x
Primary VRAM: 8192 MB
Supported MSAA Modes: 2x 4x 8x 16x

Sound card:
Audio device: Realtek ALC1150

Memory:
RAM: 32022 Mb

Miscellaneous:
UI Language: English
LANG: en_GB.UTF-8
Total Hard Disk Space Available: 8298233 Mb
Largest Free Hard Disk Block: 5300260 Mb
VR Headset: None detected

Recent Failure Reports:

Compatibility Report

• Name of the game with compatibility issues: Call of Duty: Modern Warfare 3
• Steam AppID of the game: 42680

System Information

• GPU: AMD Radeon R9 390
• Driver/LLVM version: Mesa 18.1.0-rc4
• Kernel version: 4.18.19-041819-generic
• Link to full system information report as Gist:
• Proton version: 3.16-4 / 3.16.6 Beta

I confirm:

• [x] that I haven't found an existing compatibility report for this game.
• [x] that I have checked whether there are updates for my system available.

Proton log

Symptoms

crash when is starting

Reproduction

Install and run singleplayer

https://gist.github.com/barfin/15c25fef43befc0d4e7d5a68dd946bd2
it's still the same on latest proton version at this time (4.11-7)
while multiplayer works perfectly fine out of the box, there are no known workarounds to make single player work

however it seems on winehq that some people made it works before with wine , single player included https://appdb.winehq.org/objectManager.php?sClass=version&iId=24738

so I got it to work but not with proton

1. I installed steam for windows with wine ,wine-4.0.2 (Ubuntu 4.0.2-1), the one that comes with ubuntu 19.10 (i.e no special repository etc. )
2. I copied the app manifests files from my Linux steam (where the game was already installed without success with proton etc.) and I created a symlink of common in the "steam for window folder
3. I configured wine to have a virtual desktop
4. I launched steam with wine, and launched call of duty from there

the games launch !!! (I read elsewhere the virtual dekstop configuration was the missing step)

don't know if it's useful to proton developer @kisak-valve ?
(I can provide more detailled steps if one of them is not clear)

@allan-simon it looks like Valve CEG DRM workaround. Thanks for sharing with us!

The singleplayer campaign and special-ops (solo) runs, but the performance is abysmal and at times almost not playable. I tried the lowest, optimized and highest graphics settings, w/wo vsync and a plethora of common launch options.
https://gist.github.com/309cdd5eabbaa99cabcf7c49e197976f

I was able to slightly improve the fps by running with PROTON_USE_WINED3D=1, but that made all shadows, lights and effects flicker, while still being well below the native performance on Windows.
https://gist.github.com/9fadb4a1e1d3983a2a8ab2c28ac08b49

Also the multiplayer seems to be working (and I could create a private lobby), but I couldn't find any games or players. However when trying to find or host an online spec-ops match it gets stuck on "connecting to online services" and then fails with "server is not available at this time, please try again".
https://gist.github.com/78a6d8c7de4bcdd048e540108e091251

Same here, abysmal performance with 6.3.8rc or experimental. Game works fine with the same dxvk version when run with wine+steam. Thats on a Ryzen 3700x+6900XT.

This seems to at least load now, but I just get a black screen. Did anyone else have the same problem and if so how did they fix it?

Using an i5-9400 and an RTX 2070 Super, the game hangs around 24-27FPS during gameplay, 36-41 during the pre-mission videos that play between levels. My settings are identical to CoD4 and MW2, both of which are consistent 60FPS. Not sure what's different about 3.

Distro - Fedora Linux 36
Kernel - 5.18.13-200.fc36.x86_64
CPU - Intel i5-10400
GPU - Nvidia RTX 3060
RAM - 16GB

The game runs with, what it seems like, an artificial FPS cap at 45FPS. No matter the graphical settings or resolution. From my own troubleshooting, I've found out that this artificial fps cap is supposedly a typical issue with a cracked/pirated game. Which is extremely strange, cause I've bought this through Steam. I don't know if it's some sort of licencing issue with a certain build of the game, or the game flags running through Steam Play as a pirated copy. The only solution that made me power through this game, at this point, is to set a 30fps lock with DXVK_FRAME_RATE=30. That unfortunately makes all the loading cutscenes a stuttery mess. The game also crashes when running with MangoHud immediately. I haven't tried Gamescope, as the one in Fedora repo is very old and doesn't support Nvidia yet.

Compatibility report

Name of the game with compatibility issues: Call of Duty: Modern Warfare 3

Steam AppID of the game: 42680

System information

-GPU: RTX 3060
-Driver/LLVM version: 535.54.03
-Kernel version: 6.3.8-200.fc38.x86_64
-Link to full system information report as Gist
-Proton version: 8.0 Experimental/ 7.0-6

Symptoms

Game doesn't run on either year old Proton that it used to be able to run, as well as newest 8.0 Experimental.
I've tried running it first with 8.0 Experimental, but I can't run anything through that recently, so after a mandatory reboot I tried 7.0-6. That doesn't work as well.

Reproduction

Launch the game.

Logs
MW3 Proton 7_0-6.log
MW3 Proton Experimental.log