Stage 1: Further adapt the AT intervention Before conducting the RCT, the investigators will use a multi-step process to adapt our already developed AT intervention for use by the target populations (i.e., cancer survivors and caregivers). These iterative steps include modifying content, user testing and eliciting feedback, and refining. Specifically, the investigators will review all communication messages in the current AT program and modify them to ensure that they are applicable to cancer survivors and caregivers and to both sexes. Then, the investigators will evaluate the AT content applicability, comprehensibility, and linguistic simplicity and clarity with \~10 cancer survivors or caregivers. The investigators will ensure that approximately half of these testing users are women and that the whole testing sample is demographically diverse. Using input and feedback from these testing users, the investigators will revise the AT further if needed. These series of tests and user-feedback sessions to refine the content further and to debug the system will go through an iterative process as needed. AT content taps on theoretical constructs of the Phase-Based Model (PBM)-a theoretical framework specific to smoking cessation used in our JITAI.

Stage 2: The pilot RCT Participant recruitment. Research staff will review medical records of cancer patients receiving care at the 2 hospitals in the past 2 years, screen for their smoking status documented in the records, and contact those who smoked for further screening. To recruit caregivers, research staff will contact random cancer patients who did not smoke and ask if they have a caregiver and if the caregiver smokes. Given the pilot nature of this study, the investigators propose to recruit independent groups of cancer survivors and caregivers who smoke, i.e., no dyads of smokers, to avoid potential interpersonal interactions.

Baseline assessment. Enrolled participants will complete a 45-minute baseline self- or assisted interview, managed and delivered by REDCap. Participants will be randomly assigned to SC or AT by the REDCap randomization module (simple, 1:1). Smartphones will be loaned to participants as needed. All participants will complete a brief training session on smartphone use and the Insight app. The Insight app also includes a help button for instructions on how to use each feature, which participants can review at any time.

Treatment groups. SC consists of brief advice to quit smoking delivered by research staff, self-help written materials (the WHO's "A guide for tobacco users to quit" that the investigators have translated to and validated in Lao), and a 2-week supply of NRT (transdermal patches). AT consists of all SC components plus a fully automated smartphone-based JITAI that involves proactive, interactive, and personalized messages, images, or videos in Lao. Adapted from the parent study and based on the PBM, AT content is designed to increase motivation, self-efficacy, and use of coping skills and reduce nicotine withdrawal symptoms and stress. AT will begin immediately after enrollment and continue for 12 weeks (about 2 messages/images/videos per day, delivered at participants' preferred time). Quit date is set at day 14 post-enrollment for AT and SC participants. JITAI content for AT participants each week will be personalized and tailored to each participant's baseline information (e.g., sex, cancer types, caregiver status, and current health conditions), current PBM phase, and responses to the brief weekly EMAs that drive AT (see Measures). Our AT only targets cigarette smoking because it is the most common type of tobacco used by Lao smokers (95%).