This randomized controlled trial aims to investigate the effect of combined Progressive Muscle Relaxation (PMR) and Diaphragmatic Breathing (DB) techniques on sleep disturbances among patients receiving chemotherapy. Sleep disturbances are common among cancer patients undergoing chemotherapy and may negatively affect physical recovery, emotional well-being, and quality of life. Participants will be randomly assigned to either an intervention group receiving PMR and DB training in addition to routine care or a control group receiving routine care alone. Sleep outcomes will be assessed using the Pittsburgh Sleep Quality Index (PSQI), sleep diary records, and wearable sleep monitoring devices. The study seeks to determine whether the combined intervention can improve sleep quality and reduce sleep-related problems in chemotherapy patients.