Community-Acquired Pneumonia (CAP): This is the most likely diagnosis given the patient's age and symptoms. Elderly individuals are more susceptible to pneumonia due to decreased immune function and potential comorbidities. CAP is a common cause of cough and fever in this demographic.

Influenza: Given the symptoms of cough and fever, influenza is a plausible diagnosis, especially during flu season. The elderly are at higher risk for complications from influenza.
Chronic Obstructive Pulmonary Disease (COPD) Exacerbation: If the patient has a history of COPD, an exacerbation could present with cough and fever, among other symptoms.
Bronchitis: Acute bronchitis could also present with these symptoms, though it's less common in the elderly to present with fever.

Pulmonary Embolism: Although less likely, pulmonary embolism can present with cough and fever, and it is critical not to miss this diagnosis due to its high mortality rate if untreated.
Tuberculosis (TB): Especially if the patient has been exposed to TB or has risk factors such as immunocompromised status, TB should be considered as it can present with chronic cough and fever.
Lung Cancer: In an elderly patient with a new onset of cough and fever, especially if there's a history of smoking, lung cancer should be considered, as it can present with these symptoms among others.

Pneumocystis jirovecii Pneumonia (PCP): This is more common in immunocompromised patients, such as those with HIV/AIDS, but could be considered in an elderly patient with severe immunodeficiency.
Q Fever: A zoonotic disease caused by Coxiella burnetii, which can present with pneumonia among other symptoms, though it's less common.
Psittacosis: Caused by Chlamydophila psittaci, typically associated with exposure to birds, it can cause pneumonia and should be considered if there's an appropriate exposure history.