Here are the Call of Duty: Vanguard System Requirements (Minimum)

CPU: Intel Core i3-4340 or AMD FX-6300.
RAM: 8 GB.
VIDEO CARD: NVIDIA GeForce GTX 960 or AMD Radeon RX 470 - DirectX 12.0 compatible system.
DEDICATED VIDEO RAM: 2048 MB.
PIXEL SHADER: 5.1.
VERTEX SHADER: 5.1.
OS: Windows 10 64-Bit.
If you can't find Vanguard or Battlenet within Windows Defender Firewall's allowed app settings, click the Allow another app button. Then click Browse to select Vanguard or Battle, and press the Open and Add buttons. After adding those apps, you can configure their firewall settings as outlined above.