Good make ahead recipe. You can even make it a day ahead -- the flavours will get a chance to marry. Good as a side "relish" to serve with Mexican food, or chicken or fish.
For the corn, use either thawed frozen kernels or canned corn kernels. You can omit the ground cumin if you don't have any. You can swap parsley for the fresh coriander. If you have green onions to use instead of the onion, that is also a nice swap to make.