Assalamualaikum.. Recently I have doing a lot of researches on shrik. And sometimes I play pubg mobile game.And when you get knocked out in the game sometimes your teammates have to save your life... So is it shrik to say 'my teammates save my life'.Because life and death is in Allah's hand..
No, the phrase "saving a life" cannot considered Shirk since it is used in the Quran:
Because of that We ordained for the Children of Israel that if anyone killed a person not in retaliation of murder, or (and) to spread mischief in the land - it would be as if he killed all mankind, and if anyone saved a life, it would be as if he saved the life of all mankind. (5:32)
In PUBG(As you have specified, I think it should be a video game PlayerUnknown's BattleGrounds), killing player is completely imaginary. None's live is gone and nobody is killed, rather you destroy a 3D model from memory. So when someone revive you that doesn't me he has saved your live. But for regular conversation you can say, "He saved my life" or just "He revived me". It isn't shirk.(But not actually saved any life, neither you nor Allah)