The next piece of Powers (CO-21) that will probably be constructed is from its north end at CO-83 to I-25, coming out near the north Air Force Academy exit. However, Colorado is so bereft of funding for new construction that that extension is not currently funded or scheduled. Upgrade to freeway through the Springs has totally uncertain timing. On the south end, there are conflicting plans to either extend CO-21 south around Fountain and intersect I-25 between the Pikes Peak Speedway and the Nixon power plant (sort of the "I-425" model), or even to extend it south parallel to I-25 to provide a corridor between Colorado Springs and northern Pueblo County, where there is a proposal to develop the area east of I-25 a la Pueblo West. The city of Pueblo is looking at annexing this area because of the development proposal. But, with no funding, these are just interesting lines on a map.
And, just to include some route number trivia, newly designated CO-21 (Powers) has two end-to-end route termini; on the north with CO-83 and on the south with CO-16.