Turn your graphics down.

It happening to me but my wifi never pick up cod to play but I use a app name super VPN to boost my net but you have to get the one closes to your region. Go below 110ms when you boosting the wifi. Once you see orange on some ms the region signal is slow but not too slow you can still select it but if it red the signal really bad remember even if it orange and it over 110ms you gonna lag later in the game worse.

Check if you have less GB storage. And overheating the phone can cause it to lag. If it wifi problem super VPN can fix that.