This letter presents a complex-frequency shifted perfectly matched layer (CFS-PML) formulation for the partially implicit Magnetically-mixed Newmark-Leapfrog finite-difference time-domain (MNL-FDTD) method. Its formulation is based on time-dependent Maxwell's equations in CFS-PML media and the auxiliary differential equation (ADE) of PML auxiliary variables. In the PML region, the efficiency of auxiliary variable terms of the formulated scheme is same as that of Roden's convolutional PML for Yee's FDTD. It is demonstrated that reflection error of MNL-FDTD with CFS-PML is comparable to those of the conventional explicit and implicit FDTDs with CFS-PML.