The aim of this study is to examine the impact of motile gyrotactic microorganisms on threedimensional (3D) cylindrical geometry attached to a Cross-fluid flow mathematical model. The motion of the microorganisms is assumed to be governed by gyrotaxis, which is the tendency of the organisms to orient and swim perpendicular to fluid flow gradients.The study will incorporate the effects of the Cross fluid flow model with infinite shear rate viscosity, 3D cylinder geometry, and microorganism behavior on the resulting distribution and concentration of the organisms. For the inspection of the velocity profile of the Cross nanofluid, the inclined magnetic field is scrutinized. The temperature of Cross nanofluid and its concentration is also studied with several facts. Mass flux and heat flux values for motile microorganisms and nanoparticles are calculated through statistical graphs. Brownian motion parameter gives a lower concentration of nanoparticles, about 81.19% and 77.53% reduction is found in the concentration of motile microorganisms. These results will provide insights into the behavior of these microorganisms in