All munchkin sets can be played with each other but expansions work best with the main/deluxe sets they are related to.
Munchkin 7: Cheat With Both Handsreplaces Munchkin Blender and Munchkin 7: More Good Cards, which are both out of print. More specifically, Cheat With Both Hands reprints Munchkin Blender, but with the brown fantasy Munchkin color scheme instead of the original purple and white; this set has also been renamed Munchkin 7 as the original Munchkin 7 had reprinted many of the cards in Munchkin Blender but also had a few original ones. These original cards are available in the Munchkin Monster Enhancers booster pack.
Thus, the combination ofCheat With Both HandsandMunchkin: Monster Enhancersare complete replacements for the combination ofMunchkin BlenderandMunchkin 7: More Good Cards.
So what's in the set? A lot more monster enhancers and item enhancers, too. There are several new low-level monsters to help you get easy kills – until somebody takes that Sock Puppet and turns it into the Ultra-Rare Extremely Sneaky Sock Puppet With Extra Cheese...