A:Answer Yes, but...
The SSD is simply the physical space where games and programs are stored. Yes it can improve performance but it usually is not the bottleneck to gaming unless you can not physically fit the game onto your computer. There are exceptions as faster drives swap data faster but as long as you are storing it on a newer SSD you should be good.
RAM however, will increase the performance gain quite a bit in many titles especially when you consider windows will suck up 4gb on its own. COD WW2 recommends 12gb of ram so 16gb should be more than sufficient. It does however recommend 6gb of VRAM(the dedicated graphics processors video memory) so keep in mind lowering shadows, details a bit and rendering distance will help. If it still lags you can try lowering the resolution(often the biggest saver for performance) from FHD 1920x1080 to HD 1366 × 768 and switch tto full screen? Many games have different performance issues and tweaks that help a lot so try a few and do an intternet search tto improve performance in your particular game.
Also, never play games with your browser open in the background. Google chrome is taking up 1gb of my ram as I am just typing this :)