Lost mobile game

Hello, when I was younger I played a lot of mobile games until my middle ages but there was this game in specific I played a lot. U were a guy w a gun, u ran left and right there was no end. The only end was your hp. U had to shoot zombies to get some coins and with those u would upgrade your hp, damage and I think you could upgrade your gun as well. I played it on a Microsoft phone in 2018.