Exercise to Boost Response to Checkpoint Blockade Immunotherapy

30 minutes of moderate exercise on an arm ergometer, a cycle ergometer, or a treadmill prior to each administration of standard of care checkpoint blockade immunotherapy across all cycles

* Inclusion Criteria: * Age ≥ 18 years * Able to read and speak English fluently * Capable of giving informed consent * Reported ability to complete 20-30 minutes moderate exercise per positive response to "can you currently walk unaided for six minutes or more?". * Scheduled for first-time checkpoint blockade immunotherapy with FDA-approved drugs, including avelumab, cemiplimab, ipilimumab, nivolumab, pembrolizumab or relatlimab in the absence of other therapies (e.g. targeted therapy) * Melanoma patients (adjuvant setting) * Melanoma patients (neoadjuvant setting) * cuSCC patients (neoadjuvant setting) * Merkel cell carcinoma patients (neoadjuvant setting) Participants may also be required to have a full COVID vaccination series; the most up-to-date best practice guidelines for research at Moffitt Cancer Center will dictate the need for such a vaccination series. Exclusion Criteria: * Presence of medical conditions, such as severe cardiovascular disease for which an exercise intervention may not be warranted. * Presence of major postoperative complications for which an exercise intervention may not be warranted.