Here are a few things to note before delving any deeper: If the Server Status for the game is at DEFCON 5, there are a number of steps that you can take to improve the quality of your connection.
If the Server Status for the Call of Duty game you’re playing is not at DEFCON 5 indicating that all online services are fully operational, you may encounter lag or connectivity issues until the status has returned to DEFCON 5. If you are experiencing latency (commonly known as lag) while playing Call of Duty online, your first step should be to check the server status for your platform and for the Call of Duty game you are playing.
For help with Call of Duty: Black Ops III, check out Call of Duty: Black Ops III Lag and In-game Performance.