Actually, there were plans to invade Switzerland. The invasion in on itself was not a priority, and the operation likely would've proceeded as planned in the event of a Soviet defeat. The following factors were taken into consideration that prevented the invasion of Switzerland from being a priority.

• Switzerland's terrain is well suited for defense, and it would've drawn excess German resources for little strategic gain.
• Switzerland was well prepared to defend itself in the event on an invasion. Including but not limited to mobilizing the entire nation, fortifying positions through the country, stockpiling supply's required for a long term in the Swiss alps, and even rigging many roads and bridges to blow as soon as the Nazi's arrived.
• Switzerland provided economic intensives, including allowing the use of it's rail system, and through it's policy of neutrality, continued to trade with Germany.

To conclude, Germany was going to invade Switzerland, but they managed to delay it long enough for Germany to be defeated.