The normalized dijet pseudorapidity distributions in pPb collisions can reveal the nuclear modifications of parton distribution functions (nPDF). Measurements as a function of average dijet transverse momentum could enable the test of the nPDF at different Q^2 scales. Moreover, recent theoretical studies based on NLO calculations show that the constraining power of pPb data on nPDF fits can be improved by the knowledge of the corresponding measurements in pp collisions. In this talk, the updated dijet pseudorapidity measurements in pPb collisions at 5 TeV in various of dijet transverse momentum ranges, as well as the corresponding reference distributions in pp collisions collected in 2015, will be presented. The measured distributions are compared to pQCD calculations with different sets of proton and nuclear PDFs.