Really? The company that owns Windows feels that it doesn't have enough foothold on PCs? Really? If Nadella is talking about PC gaming, then I get it. I find it difficult to believe that they are serious about it. Remember that Games for Windows thing that Microsoft epically failed to act on?
They don't need to buy game studios, they could do fabulously by releasing old Xbox exclusives on PC. If they released that Halo Collection on PC, I'd buy it right away.