According to the current rumors, NVIDIA is working on a successor to the Shield, which should be powered by the company's impressive Tegra X1 processor.
The reports are coming from something being spotted on the Bluetooth Special Interest Group and the Wi-Fi Certification Alliance, which came a couple of months ago, but now we're seeing Zauba with a new report. The new report states that the next-gen Shield should rock LTE capabilities, as well as LPDDR4 RAM.
NVIDIA has given it an awesome codename of "Loki" which would make sense as Shield is part of the Marvel universe, and Loki is Thor's brother (and one of the best things about the Marvel Cinematic Universe - thanks Tom Hiddleston). The new Shield 2 should be powered by NVIDIA's Tegra X1 processor, which has support for 4K 60FPS, and even 1080p at 120FPS. It rocks an 8-core processor, DX12 support and 256 GPU cores, so we can expect the next Shield to be an even bigger portable gaming powerhouse.