The goal of this research study is to look at how live, online group exercise compares to recorded videos for helping increase physical activity levels, improve physical fitness and quality of life, and reduce loneliness among those living with and beyond cancer. The following aims have been established for this study: * Aim 1: Examine the effect of a group-based videoconference physical activity (PA) intervention on moderate to vigorous physical activity \[MVPA\] (i.e., aerobic and resistance exercise). * Aim 2: Examine the effect of the intervention on additional health-related outcomes including physical fitness (i.e., aerobic endurance, muscular strength), and quality of life at both timepoints. * Aim 3: Explore potential mediators and moderators of intervention effects. We will examine mediators (e.g., self-efficacy, outcome expectations, group cohesion) and moderators (e.g., age, cancer stage, neighborhood walkability) of the intervention on MVPA. * Exploratory Aim: Determine whether a group-based videoconference PA intervention reduces loneliness among cancer survivors. Researchers will randomize participants into one of two guided exercise groups that are 12-weeks long in duration. Participants will be asked to complete online fitness assessments and surveys as well as wear a physical activity monitor device and watch a few times throughout the study. The whole study is 9-months long in duration with a 6-month free-living period where no study activities will take place.