已知圆$O:x^2+y^2=1$和点$A\left(-2,0\right)$,若定点$B\left(b,0\right)\left(b\ne -2\right)$和常数$\lambda$满足:对圆$O$上那个任意一点$M$,都有$\left|MB\right|=\lambda \left|MA\right|$,则:$b=$；$\lambda =$.