The third season of CoD: Modern Warfare and Warzone started on April 8th. However, many players cannot download the approximately 16 GB update from Battle.net because the Download painfully slow at times running.
Activision Blizzard is aware of the situation and indicates in the launcher and on the official website that it is currently closed limited download rates
People are simply more at home and spend their time using the internet and games. So it happens that especially Rush hour download rates are sometimes considerably limited, especially for large data packages such as extensive game updates.
These tricks can help
If you have already set the download rate to 0 (0 = unlimited) in the settings of the Battle.net client, your client should use the maximum available bandwidth. If Call of Duty is charging too slowly, try one of the following tips:
Switch region at Battle.net: Since the download rates are linked to the respective region, you can use a simple trick. First pauses the ongoing download. The region now changes from "Europe" to "America". Now start the download again.
After the download has started again, you should notice an improvement in the download speed. If that doesn't help either, you still have the virtual switch to a far away server.
Use VPN: If you use a VPN, you can connect to a server in a country where Internet usage is probably not high. Use a world clock to find a place where it is currently early morning, for example.
Once you have connected to the remote server, Battle.net restarts and starts downloading. Now you should notice a significant improvement in the download rates for CoD: Modern Warfare, Warzone and Co.