  The redshifted 21cm radio signal has emerged as an important probe for
investigating the dynamics of the dark age Universe (recombination to
reionization). In the current analysis, we explore the combined effect of
primordial black hole (PBH) evaporation and the baryon-dark matter (DM)
interaction in the 21cm scenario. The variation of brightness temperature shows
remarkable dependence on the DM masses ($m_{\chi}$) and the baryon-DM
cross-sections ($\overline{\sigma}_0$) besides the influences of the PBH
parameters (mass $\mathcal{M_{\rm BH}}$ and initial mass fraction $\beta_{\rm
BH}$). We address both upper and lower bounds on $\beta_{\rm BH}$ for a wide
range of PBH mass in presence of different $m_{\chi}$ and $\overline{\sigma}_0$
by incorporating the observational excess $\left(-500^{+200}_{-500}\: {\rm
mK}\right)$ of EDGES's experimental results. Finally, we address similar limits
in the $m_{\chi}$ - $\overline{\sigma}_0$ parameter plane for different PBH
masses.
