  The long-awaited $B_s\to \mu^+\mu^-$ mode has finally been observed at rate
consistent with Standard Model, albeit lower by 1.2$\sigma$. There is some hint
for New Physics in the rarer $B_d^0 \to \mu^+\mu^-$ decay, especially if the
currently 2.2$\sigma$-enhanced central value persists with more data. The
measurement of $CP$ violating phase $\phi_s$, via both $B_s\to J/\psi K\bar K$
and $J/\psi\pi\pi$ modes, has reached Standard Model sensitivity. These
measurements stand major improvement when LHC enters Run 2. Concurrently, the
$K_L\to\pi^0\nu\bar\nu$ and $K^+\to\pi^+\nu\bar\nu$ modes are being pursued in
a similar time frame. We illustrate the possible correlations between New
Physics effects in these four modes, using the fourth generation as example.
While correlations may or may not exist in other New Physics models, the four
generation model can accommodate enhancements in both $B_d^0 \to \mu^+\mu^-$
and $K_L\to\pi^0\nu\bar\nu$.
