  We analyze incommensurate charge-density-wave (CDW) and pair-density-wave
(PDW) orders with transferred momenta $(\pm Q,0)$/$(0,\pm Q)$ in underdoped
cuprates within the spin-fermion model. Both orders appear due to exchange of
spin fluctuations before magnetic order develops.We argue that the ordered
state with the lowest energy has non-zero CDW and PDW components with the same
momentum. Such a state breaks $C_4$ lattice rotational symmetry, time-reversal
symmetry, and mirror symmetries. We argue that the feedback from CDW/PDW order
on fermionic dispersion is consistent with ARPES data. We discuss the interplay
between the CDW/PDW order and $d_{x^2-y^2}$ superconductivity and make specific
predictions for experiments.
