[The] latest version of U.S. Tomahawk (BGM-109 Block 4) missile, is getting upgraded so that it can hit moving targets. This is mainly intended to turn the Tomahawk into an anti-ship missile, although it can also hit moving land targets. Currently, the Block 4 Tomahawk costs about $1.7 million each, weighs 1.4 tons, has a range of 1,500 kilometers and carries a half ton warhead. It moves to its target at a speed of 880 kilometers an hour. Since production began four years ago, 1,300 have been made since.
The United States is developing a successor to the Tomahawk cruise missile, that will be heavier (2.2 tons, versus 1.4 tons), have a longer range (2,000 kilometers versus 1,500) and a one ton warhead (twice the size of the Tomahawks.) The new missile will be stealthier, and use a combination of guidance and targeting systems (to improve the chances of success). Price will probably be the key factor in whether this new missile ever enters service. The new Cruise Missile XR (for Extended Range) will probably cost twice that, or more.
Moves and counter-moves. This doesn't address the problem of getting air cover for Taiwan in the face of China's modernizing air force, but it does address Chinese ships in the Taiwan Strait.