• Able to understand and willing to sign a written informed consent document

• HIV positive. Documentation of HIV-1 infection by means of any one of the following:

‣ Documentation of HIV diagnosis in the medical record by a licensed health care provider;

⁃ Documentation of receipt of antiretroviral therapy (ART) (at least two different medications that do not constitute a prescription for pre-exposure prophylaxis \[PrEP\] or post-exposure prophylaxis \[PEP\]) by a licensed health care provider. Documentation may be a record of an ART prescription in the participant's medical record, a written prescription in the name of the participant for ART, or pill bottles for ART with a label showing the participant's name;

⁃ HIV-1 ribonucleic acid (RNA) detection by a licensed HIV-1 RNA assay demonstrating \> 1000 RNA copies/mL;

⁃ Any licensed HIV screening antibody and/or HIV antibody/antigen combination assay confirmed by a second licensed HIV assay such as a HIV-1 Western blot confirmation or HIV rapid multispot antibody differentiation assay.

∙ Note: The term licensed refers to a kit that has been certified or licensed by an oversight body within the participating country and validated internally (e.g., U.S. Food and Drug Administration \[FDA\]).

∙ WHO (World Health Organization) and CDC (Centers for Disease Control and Prevention) guidelines mandate that confirmation of the initial test result must use a test that is different from the one used for the initial assessment. A reactive initial rapid test should be confirmed by either another type of rapid assay or an E/CIA that is based on a different antigen preparation and/or different test principle (e.g., indirect versus competitive), or a Western blot or a plasma HIV-1 RNA viral load

• Receiving antiretroviral therapy and CD4 count at least 200 cells/uL within 6 months of registration (due to increased risk of LDCT false positivity with CD4 count \< 200cells/uL)

• Age 45-80 years. This age restriction reflects lung cancer risk and appropriateness for lung cancer screening; in epidemiologic studies lung cancer emerges 5-10 years earlier in PLWH, and therefore this is an appropriate risk group for screening. Although younger persons are likely to benefit more from smoking cessation as a lung cancer prevention measure, the risk/benefit ratio associated with lung cancer screening is unlikely to be optimal at ages \< 45 years for PLWH

• Biochemically confirmed current smoker (exhaled carbon monoxide \[CO\] \>= 7 parts per million)

• Meets United States Preventive Services Task Force (USPSTF) criteria for LDCT (age 50-80 and \>= 20 pack-years smoking) or high-risk but not meeting USPSTF (age 45-49 and \>= 20 pack-years smoking)

• Possession of a smartphone that can support Positively Smoke Free Mobile (PSF-M) (\> 95% of subjects had eligible phones in prior trials although researchers will include specific study screening questions assessing for adequate smartphone for the intervention)

• Sufficient literacy; \>= 4 on the Rapid Estimate of Adult Literacy in Medicine-Short Form (REALM-R) literacy scale