An Intel Core i5-2500 CPU is required at a minimum to run Call of Duty: Modern Warfare. However, the developers recommend a CPU greater or equal to an Intel Core i7-6700 to play the game. Provided that you have at least an AMD Radeon R9 380 graphics card you can play the game.
In order to max out Warzone, your computer should have at least a GeForce GTX 970 or a Radeon R9 390 for its GPU. In your CPU slot, you are looking at needing something along the lines of the Intel Core i5-2500K or the AMD Ryzen R5 1600X.