Correlation between <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>H</mml:mi> </mml:math> -linear magnetoresistance and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>T</mml:mi> </mml:math> -linear resistivity in

Linear-in-temperature resistivity ($T$-linear) and linear-in-field ($H$-linear) magnetoresistance (MR) are two typical characteristics of the strange-metal state in high-temperature (high-${T}_{\text{c}}$) superconductors. Unraveling the relationship between the two phenomena may provide critical insights into the underlying mechanisms of strange metallicity and superconductivity. In this study, we investigate the high-field MR of the trilayer cuprate ${\text{Tl}}_{\text{2}}{\text{Ba}}_{\text{2}}{\text{Ca}}_{\text{2}}{\text{Cu}}_{\text{3}}{\text{O}}_{\text{10}+\ensuremath{\delta}}$ and perform a comparative analysis with other high-${T}_{\text{c}}$ superconductors, including single-layer cuprates and iron-based systems. In all systems, MR exhibits an ${H}^{\text{2}}$ dependence at high temperatures, which gradually evolves to an $H$-linear dependence as temperature decreases. Remarkably, we found that the ratios of $H$-linear to $T$-linear coefficients are on the same order of magnitude (with the mean value of $0.40\ifmmode\pm\else\textpm\fi{}0.22$) across a broad range of materials, despite significant differences in lattice structure, Fermi surface geometry, and superconducting transition temperature. A further combination with MR simulations suggests momentum-dependent anisotropic scattering may be the origin for $H$-linear MR in various high-${T}_{\text{c}}$ superconductors, which may also be the origin of $T$-linear resistivity.