How to get non white color tiles when I set the 'rescale' parameter

[XiaoYang943]

Hello,
This is a slope data from DEM.
When I set rescale param(0 to 5).
Then I get a white color tile.
How to remove white color？It is unused.
Thanks.

[XiaoYang943]

I used 'rescale' because I want to filter the pixel value.
For example, I only want to get 0 to 5 of slope.
Can you give me some suggestion?
Thanks. Good Luck for you.

[XiaoYang943]

The 'rescale' is not used to filter data.It is my wrong.
How to filter when i use '/cog/tiles' endpoint?
Thanks.