Simply put, I want to get 7 Days to Die and my friend (who lives in Russia) said he will buy it for me as a gift rather than give me money because it is cheaper for him. However, I was wondering if it is region locked? The link is here.
Since 2014, Steam games bought in Russia cannot be played outside Russia. Valve put this restriction in place after the ruble crashed, because they didn't want to raise prices on Russian customers, but did want to prevent arbitrage exploits like the one your friend is suggesting.
Think of the policy this way: the price is lower in Russia only because the games can't be bought by or gifted to non-Russian accounts. If they still could be, Valve would be forced to make the prices match prices outside Russia, and lose a lot of Russian customers due to the massive price increase.
In this specific case, 7 Days to Die would appear to not be region locked, so your friend could send it to you. This thread was useful, (it was what I used to find out in this case). Basically, by tracking the game's ID down in the SteamDB, then using the subID of the various versions of products, I wasn't able to find anything that indicated that it would be locked to the region. I also found the steam page on this subject matter, and it was quite informative.