If you can wait, then wait. If not then buy whatever laptop now that you feel is good for your needs.
To the best of my knowledge, the mobile variants of the Pascal GPU are expected to be released mid 2016 which means June / July. However, you may need to wait a bit longer for more laptops with nVidia's next gen GPU to appear in the market that would actually interest you.
I think there should be a decent number of laptops with nVidia's Pascal GPUs in August because of back to school sales. There should be even more around Thanksgiving in time for the Christmas shopping frenzy. But I would say that if you can hold out until late July / early August, then do so. Otherwise buy something now if it catches your eye.
As for Intel's new CPUs... Kaby Lake... I have not kept up with mobile CPUs in the past few month. Why? Because I am trying to prevent myself from buying a new laptop. I do not expect much of a performance increase in terms of processing power. Probably only about 5% better performance compared to a Skylake CPU with the same number of core and same clockspeed. Some bits of info that I do know are as follows:
- Native USB 3.1 support
- Full hardware support for 10-bit HPEC and VP9 video to more easily decode and playback 4k video
- Kaby Lake is only compatible with Windows 10. It will not support previous versions of Windows.