I’m envisioning a setting in which human beings have altered themselves significantly to be able to live on alien worlds without significant terraforming.

One type of transhuman needed would be one that could live on extremely cold, often dark planets, moons, or areas of planets - like Mars, Titan, or the dark side of a tidally locked planet.

What adaptations would be needed for a humanoid creature to survive, even thrive, in the temperature range of -50C to -200C (I’m aware that’s an enormous range, but you could have subspecies for different subranges of that) and in very dim lighting (even pitch black). 

I initially thought infrared vision, but I’m not sure how useful that would be when it’s so incredibly cold. SONAR, perhaps? What else would be useful or necessary to survive in such environments?