MSI has just unveiled their M.2 Shield. This new feature will appear on their next-generation (Z270) socket LGA1151 motherboards. The M.2 shield is an aluminum heatspreader that acts as a full-length cover over your motherboards M.2-2280 slots. It is hinged right by the M.2 connector. On the inside the cover has a non-conductive thermal pad which lets it make contact with your M.2 SSDs controller and NAND chips and transferring heat to the heatspreader.
MSI says that the M.2 Shield will lower temperatures and can even reduce throttling on some high performance PCIe M.2 SSDs. Many super fast M.2 solid state drives have a reputation of getting so hot that it reduces performance. This small piece of aluminum should help with that.