Is Samsung 950 Pro compatible with MacBook Pro 15’ mid 2014?

The best source for that information is OWC. The SSD is compatible with operations, but not sure if it will plug into your Mac's edge-card connector. Apple tends to use a different pin-out that is only compatible with the proprietary version of the SSD.

fuentesdiego wrote:

Can Someone help me please cause some people said it’s compatible because m.2 but I’m not sure please or some ssd high speed compatible

Some people claim that adapters work, but Apple really has proprietary SSD pinouts and some proprietary way of doing it. The only aftermarket replacements that are guaranteed to work are sold by OWC and Transcend since they've cracked the pinout/format. Here's an article on all this stuff:

http://www.ssd-for-mac.com/blog/files/compatible-m2-ssd-macbook.php

All things considered, this market is just too deep and complex and filled with too many variables for me to cover well. True hardware upgrade nerds groove on figuring all these specifics out and performing the upgrade themselves. But the average Mac user just wants a simple, affordable solution. For them I simply recommend whatever off the shelf, direct plug in Apple spec modules they can order from Transcend or OWC and leave the adapter / retrofit M.2 SSD Apple solutions to the kind of guys that prefer cheaper DIY complexity over retail solutions.